Search Results (112)

The design and optimization of drive distribution strategies are critical for enhancing the performance of Formula Student electric racing cars, which face demanding operational conditions such as rapid acceleration, tight cornering, and variable track surfaces. Given the increasing complexity of racing environments and the need for adaptive control solutions, a multi-mode adaptive drive distribution strategy for four-wheel-drive Formula Student electric racing cars is proposed in this study to meet specialized operational demands. Based on the dynamic characteristics of standardized test scenarios (e.g., straight-line acceleration and figure-eight loop), two control modes are designed: slip-ratio-based anti-slip control for longitudinal dynamics and direct yaw moment control for lateral stability. A CarSim–Simulink co-simulation platform is established, with test scenarios conforming to competition standards, including variable road adhesion coefficients (μ is 0.3–0.9) and composite curves. Simulation results indicate that, compared to conventional PID control, the proposed strategy reduces the peak slip ratio to the optimal range of 18% during acceleration and enhances lateral stability in the figure-eight loop, maintaining the sideslip angle around −0.3°. These findings demonstrate the potential for significant improvements in both performance and safety, offering a scalable framework for future developments in racing vehicle control systems. Full article

The electromechanical braking (EMB) system is an important component of intelligent vehicles and is also the core actuator for longitudinal dynamic control in autonomous driving motion control. Therefore, we propose a new mechanism layout form for EMB and a feedforward second-order linear active disturbance rejection controller based on clamping force. This solves the problem of excessive axial distance in traditional EMB and reduces the axial distance by 30%, while concentrating the PCB control board for the wheels on the EMB housing. This enables the ABS and ESP functions to be integrated into the EMB system, further enhancing the integration of line control and active safety functions. A feedforward second-order linear active disturbance rejection controller (LADRC) based on the clamping force of the brake caliper is proposed. Compared with the traditional clamping force control methods three-loop PID and adaptive fuzzy PID, it improves the response speed, steady-state error, and anti-interference ability. Moreover, the LADRC has more advantages in parameter adjustment. Simulation results show that the response speed is increased by 130 ms, the overshoot is reduced by 9.85%, and the anti-interference ability is increased by 41.2%. Finally, the feasibility of this control algorithm was verified through the EMB hardware-in-the-loop test bench. Full article

With the rapid advancement of urban underground space development, shield tunnel construction has seen a significant increase. However, at the initial launching stage of shield tunnels in shallow-buried weak strata, engineering risks such as face instability and sudden surface settlement frequently occur. At present, there are relatively few studies on the reinforcement technology of the initial section of shield tunnel in shallow soft ground and the evolution law of ground disturbance. This study takes the launching section of the Guanggang New City depot access tunnel on Guangzhou Metro Line 10 as the engineering background. By applying MIDAS/GTS numerical simulation, settlement monitoring, and theoretical analysis, the reinforcement technology at the tunnel face, the spatiotemporal evolution of ground settlement, and the mechanism of soil disturbance transmission during the launching process in muddy soil layer are revealed. The results show that: (1) the reinforcement scheme combining replacement filling, high-pressure jet grouting piles, and soil overburden counterpressure significantly improves surface settlement control. The primary influence zone is concentrated directly above the shield machine and in the forward excavation area. (2) When the shield machine reaches the junction between the reinforced and unreinforced zones, a large settlement area forms, with the maximum ground settlement reaching −26.94 mm. During excavation in the unreinforced zone, ground deformation mainly occurs beneath the rear reinforced section, with subsidence at the crown and uplift at the invert. (3) The transverse settlement trough exhibits a typical Gaussian distribution and the discrepancy between the measured maximum settlement and the numerical and theoretical values is only 3.33% and 1.76%, respectively. (4) The longitudinal settlement follows a trend of initial increase, subsequent decrease, and gradual stabilization, reaching a maximum when the excavation passes directly beneath the monitoring point. The findings can provide theoretical reference and engineering guidance for similar projects. Full article

Metropolitan city express line tunnels are fully enclosed and often span long distances between stations, allowing multiple trains within a single interval. Traditional segmented ventilation ensures only one train per section, but ultra-long tunnels with shaftless designs introduce new challenges under fire conditions. This study investigates smoke behavior in an ultra-long inter-district tunnel during multi-train blockage scenarios. A numerical model evaluates the effects of train spacing, fire source location, and receding spacing on smoke back-layering, temperature distribution, and flow velocity. Results indicate that when train spacing exceeds 200 m and longitudinal wind speed is above 1.2 m/s, the impact of train spacing on smoke back-layering becomes negligible. Larger train spacing increases back-layering under constant wind speed, while higher wind speeds reduce it. Fire source location and evacuation spacing affect the extent and pattern of smoke spread and high-temperature zones, especially under reverse ventilation conditions. These findings provide quantitative insights into fire-induced smoke dynamics in ultra-long tunnels, offering theoretical support for optimizing ventilation control and evacuation strategies in urban express systems. Full article

Background and aims: Opioid maintenance therapy (OMT) is the first-line treatment for opioid use disorder (OUD), reducing opioid use and mortality while improving physical and mental health. However, concomitant substance use remains common, with cannabis being the most frequently used substance. This study assessed the prevalence and clinical correlates of cannabis use in OMT patients, as well as individual motivations. Methods: In this cross-sectional, single-center study, 128 OUD patients (96 male, 32 female) receiving OMT were assessed using standardized questionnaires: the Marijuana Smoking History Questionnaire (MSHQ), Cannabis Problems Questionnaire (CPQ) and the Severity of Dependence Scale (SDS). Cannabis users and non-users were compared regarding type (methadone vs. buprenorphine) and dosage of maintenance medication. Results: Cannabis use was reported by 41% of patients, 73% met criteria for cannabis dependence, 30% of the full sample. Of the patients, 85% reported cannabis-related legal issues. Common reasons for use included recreational motives (mood change, enhancement) and reduction in cravings for other substances. Cannabis dependence was significantly more common in patients receiving buprenorphine than methadone. Higher methadone doses were also associated with increased cannabis use. These results suggest a clinically relevant pattern. Conclusions: Cannabis use is highly prevalent and appears to be influenced by type and dosage of substitution medication. These findings highlight a complex interaction between opioid treatment and cannabis use, possibly involving behavioral coping or regulatory processes. Further longitudinal and placebo-controlled trials are needed to investigate the clinical and pharmacological interactions between cannabis and OMT, including effects on craving, withdrawal, and overall treatment outcomes. Full article

Background: Diabetes is rapidly increasing in developing and industrializing nations, primarily due to type 2 diabetes (T2DM). With the global prevalence of diabetes steadily increasing, estimates suggest that by 2045, nearly 548 million people will be living with the disease worldwide. Alzheimer’s disease (AD), recognized as the primary contributor to dementia in aging populations, exhibits an escalating prevalence that parallels the demographic shifts toward older age groups worldwide. This progressive neurodegenerative disorder has emerged as a critical public health challenge, with epidemiological patterns closely tracking the trajectory of population aging across industrialized and developing nations. This study investigates whether metformin may help reduce the risk of dementia. Previous studies from various countries have explored the association between metformin use and dementia risk; however, the findings have been inconsistent. Therefore, we conducted this study to examine whether the observed protective effect of metformin also applies to the Taiwanese (Han Chinese) population, potentially providing valuable insights into ethnic or regional differences in drug response. Methods: We conducted a retrospective cohort study using data from the Longitudinal Health Insurance Database 2000 (LHID2000), including 2 million individuals from 2000 to 2013. Patients with T2DM aged ≥40 years who initiated metformin between 2000 and 2005 formed the exposed group, while those starting other second-line antidiabetic medications formed the non-exposed group. Propensity score matching was used to control for age, sex, index date, and major comorbidities. Incident dementia (2007–2013) was identified using relevant ICD-9-CM codes. Adjusted hazard ratios were estimated using Cox regression with time-dependent covariates. Results: The metformin-exposed cohort demonstrated a risk reduction for dementia incidence relative to the comparator group (adjusted HR 0.472, 95% CI = 0.328–0.679). This protective association remained robust in sex-stratified analyses and age-stratified subgroups. Temporal analysis further revealed a duration-dependent risk attenuation, with extended therapeutic exposure correlating with progressive dementia risk decrement. Conclusions: Our findings suggest that metformin use may be associated with a lower risk of developing dementia in individuals with type 2 diabetes mellitus. Full article

Background: Huntington’s disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the HTT gene, with a rare juvenile-onset form (JoHD) marked by early, rigid motor symptoms. This study examined cortical and subcortical resting-state connectivity in JoHD, hypothesizing preserved cortical networks but altered striatal connectivity, in line with early subcortical atrophy despite relatively spared cortical volume. Methods: Participants included children and young adults with clinician-confirmed Juvenile-Onset Huntington’s Disease (JoHD; n = 19) and gene-non-expanded (GNE) controls (n = 64), both drawn from longitudinal studies at the University of Iowa. Resting-state functional MRI scans were analyzed to assess canonical cortical network and striatal connectivity, and linear mixed-effects models tested group differences and associations with motor, cognitive, and clinical outcomes. Results: JoHD participants showed reduced connectivity within the left somatomotor network and striatal circuits, despite largely typical cortical network connectivity. Striatal connectivity was associated with disease burden and cognitive ability, while left somatomotor connectivity was unrelated to clinical outcomes. Conclusions: These findings support the hypothesis of antagonistic pleiotropy in JoHD, where early neural advantages—such as relatively preserved or possibly enhanced cortical function—may contribute to later striatal vulnerability and degeneration. The observed left-lateralized somatomotor hypoconnectivity aligns with prior volumetric and gene expression research, highlighting the role of excitotoxic glutamatergic input and the selective vulnerability of high-functioning circuits in disease progression. Full article

Background. Poor posture is a common musculoskeletal concern in children and adolescents and may lead to spinal discomfort and long-term structural issues. While excess weight has been linked to altered sagittal alignment, the impact of sports participation on spinal posture remains unclear. This study aimed to investigate the associations between weight status, sports participation, and sagittal spinal alignment in a pediatric population. Methods. This cross-sectional study was conducted within the “Ferrari Formula Benessere” corporate wellness program and included 698 children aged 5 to 16 years. Sagittal Index (SI) was measured using a standardized plumb line technique. Body mass index (BMI) was calculated and classified according to the WHO growth standards. Sports participation was self-reported and grouped into five categories: sedentary, skill-based, power-based, mixed, and endurance sports. Results. Age was the only significant independent predictor of the SI (β = 2.45, p < 0.001), with older children exhibiting higher SI values. Although a weak correlation was observed between BMI and SI (Spearman’s r = 0.24, p < 0.001), BMI was not a significant predictor when controlling for age. No significant differences in the SI were found between active and non-active children. Among sport disciplines, the SI was lowest in power-based sports (56.7 ± 22.3 mm) and higher in endurance (62.7 ± 24.4 mm), mixed (64.5 ± 23.2 mm), skill-based (61.1 ± 22.0 mm), and non-sport (64.2 ± 24.0 mm) groups, although these differences did not reach statistical significance (ANOVA p = 0.224). Conclusions. Age appears to be the primary factor associated with sagittal spinal alignment in children, while BMI and general sports participation showed no independent effect. Although some differences emerged between sport types, these findings were not statistically significant and should be interpreted with caution. These findings underscore the need for sport-specific, longitudinal research using objective posture assessment methods. Full article

This paper presents the development of a novel aerodynamic model tailored for the Bio-Inspired Rotating Empennage (BIRE), a non-traditional fixed-wing aircraft empennage inspired by avian flight. The BIRE replaces the conventional vertical stabilizer with an extra degree of freedom for the horizontal stabilizer, which is allowed to rotate about the body-fixed x axis. This empennage is similar to the tail of a bird, and allows control of both longitudinal and lateral moments. However, such a design introduces complex nonlinear longitudinal and lateral aerodynamic interactions, not typically accounted for in most fixed-wing aircraft aerodynamic models below stall. This work presents a nonlinear sinusoidal aerodynamic model that can be used for fixed-wing aircraft with this type of empennage. Although the aerodynamic model is constructed to accurately capture the degrees of freedom of this particular empennage design, similar methods could be used to develop other aerodynamic models for non-traditional control effectors. A large dataset of low-fidelity aerodynamic data was generated using a modern numerical lifting-line algorithm, and these data were fit to the nonlinear sinusoidal aerodynamic model. A method for fitting the data is demonstrated, and the results show that the nonlinear sinusoidal aerodynamic model can be fit to the data with an accuracy of less than 10% of the maximum deviation of the aerodynamic coefficients in root-mean-square error. The underlying physics of many of the longitudinal and lateral nonlinear sinusoidal aerodynamic properties of the aircraft are discussed in detail. The methodology presented here can be extended to other non-traditional control effectors, encouraging innovative approaches in aerodynamic modeling and aircraft design. In contrast, choosing to model control effectors using the traditional, linear approach can obscure key aerodynamic behaviors key for trim and control analyses. The study’s findings underscore the importance of developing adaptable aerodynamic models to support the advancement of next-generation aircraft designs and control systems. Full article

Background/Objectives: Lumbosacral spinal stenosis (LSS) is a degenerative condition characterized by narrowing of the spinal canal and associated neuropathic pain. While mechanical compression is well-characterized, the molecular mechanisms contributing to symptom severity remain poorly understood. Neurturin (NRTN), a member of the glial cell line-derived neurotrophic factor family, has emerged as a potential mediator of neural plasticity and nociception, but its role in spinal stenosis is largely unexplored. Methods: We analyzed NRTN mRNA and protein expression in ligamentum flavum samples from 96 patients undergoing surgery for LSS and 85 non-degenerative postmortem controls. Quantification was performed using real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), Western blotting, and immunohistochemistry. Pain severity Visual Analog Scale (VAS), body mass index (BMI), diabetes, smoking, and alcohol use were assessed as modulators of NRTN expression. Results: NRTN expression was significantly elevated in LSS patients versus controls at both transcript and protein levels (p < 0.05). NRTN levels positively correlated with pain intensity (VAS; ANOVA p = 0.032 for mRNA, p = 0.041 for protein). Multivariate regression identified BMI (β = 0.50, p = 0.015) and diabetes (β = 0.39, p = 0.017) as independent predictors of increased NRTN expression. Alcohol use also showed a positive association (p = 0.046), while smoking showed no significant independent effect. Conclusions: Neurturin is upregulated in ligamentum flavum tissue from LSS patients and correlates with pain severity and metabolic risk factors. These findings suggest NRTN as a potential biomarker and therapeutic target in degenerative spine disease. Further longitudinal and mechanistic studies are warranted to elucidate its role in chronic pain and neuroinflammation. Full article

Background and Objectives. Our recent systematic review and meta-analysis of all studies on meditation as treatment for PTSD (61 studies) found a moderate effect size of Hedges’s g = −0.67 for post-minus-pre change in symptom scores. Separate tests of the four meditation categories found a large effect size of g = −1.13 for the Transcendental Meditation (TM) technique that is significantly greater than for each other category. The present follow-up used a different method, calculating effects relative to internal controls, to better characterize the effects of this meditation technique. Materials and Methods. Our study followed Prisma guidelines. Major databases, research anthologies, and bibliographies were searched for studies that used TM for treating PTSD, all military and civilian populations, and all age groups. Results. The searches located 15 controlled trials on TM that met the inclusion criteria (longitudinal and reporting sufficient statistics to calculate effect sizes), 1248 subjects total, mean age 40.5 years (range 20.6 to 54.4 years), and 46.9% males (range 0% to 100%). Using the random effects model, the pooled effect across all studies of TM compared to other treatments was g = −1.01, 95% CI = −1.29 to −0.74, p < 0.000000001. One-study removed analysis found that no study reduced the pooled effect to less than −1.0. Funnel plots indicated no risk of bias. TM was non-inferior to prolonged exposure therapy, p = 0.0001, and it worked significantly faster (p = 0.04 at week six). Conclusions. TM produced clinically meaningful reductions in PTSD for civilian and military personnel, young and older adults, and for both men and women. We recommend phase-III multisite studies comparing TM with known first-line treatments for PTSD. Full article

A fault-tolerant collaborative control strategy for four-wheel-drive electric vehicles is proposed to address hidden safety issues caused by one or more in-wheel motor faults; the basic design scheme is that the control system is divided into two layers of motion tracking and torque distribution, and three systems, including driving, braking, and front-wheel steering are controlled collaboratively for four-wheel torque distribution. In the layer of motion tracking, a vehicle model with two-degree-of-freedom is employed to predict the control reference values of the longitudinal force and additional yaw moment required; four types of sensors, such as wheel speed, acceleration, gyroscope, and steering wheel angle, are used to calculate the actual values. At the torque distribution layer, SSOD and MSCD distribution schemes are designed to cope with two operating conditions, namely sufficient and insufficient output capacity after local hub motor failure, respectively, focusing on the objective function, constraints, and control variables of the MSCD control strategy. Finally, two operating environments, a straight-line track, and a DLC track, are set up to verify the effectiveness of the proposed control method. The results indicate that, compared with traditional methods, the average errors of the center of mass sideslip angle and yaw rate are reduced by at least 12.9% and 5.88%, respectively, in the straight-line track environment. In the DLC track environment, the average errors of the center of mass sideslip angle and yaw rate are reduced by at least 6% and 4.5%, respectively. The proposed fault-tolerant controller ensures that the four-wheel-drive electric vehicle meets the requirements of handling stability and safety under one or more hub motor failure conditions. Full article

Background/Objectives: Perimenopause, impacting 80–90% of women, encompasses a range of vasomotor, urogenital, cognitive, and psychiatric symptoms associated with the fluctuation and gradual reduction of gonadal hormones. Moreover, the onset or worsening of sleep disturbances is prevalent during the menopausal transition. This narrative review seeks to elucidate the pathogenetic processes behind sleep disturbances during perimenopause and the main therapeutic options. Methods: The electronic databases PubMed, Scopus, Google Scholar, Web of Science, and Embase were queried for publications up to May 2024. Longitudinal, observational, case–control, and cross-sectional studies, as well as reviews and meta-analyses, were included in the review in order to explore the prevalence of sleep disorders during perimenopause, the pathogenetic mechanisms underlying the association between menopausal transition and sleep disorders, and the available non-pharmacological and pharmacological treatment options. Results: Sleep disturbances are common among perimenopausal women and include insomnia, sleep-related breathing disorders, and movement disorders. Fluctuations in estrogen and progesterone affect sleep quality, while vasomotor symptoms can disrupt sleep. Circadian changes, decreased melatonin production, and physiological changes associated with aging and mood disorders further exacerbate sleep disturbances. Conclusions: Managing sleep disorders in perimenopause requires an individualized approach, considering the multifactorial nature of these disturbances and providing background knowledge about the relationship between reproductive hormonal changes and sleep. Non-pharmacological treatments should be considered the first-line therapy; hormone therapy or non-hormonal pharmacological treatments can be considered according to the patients’ specific needs and risk factors. However, there is still a lack of standards on the appropriate management and treatment of sleep disorders in perimenopause. Full article

Background/Objectives: This study evaluated the effects of a novel Astragalus extract (Keyfobell powder [KFB]) composed of Astragalus membranaceus, red ginseng (Panax ginseng C. A. Meyer), and Cervi Parvum Cornu as a potential growth hormone (GH) alternative. The primary focus was placed on its impact on longitudinal bone growth through the upregulation of circulatory insulin-like growth factor (IGF)-1. Methods: We performed in vitro and in vivo experiments using a hypothalamic cell line and Sprague–Dawley (SD) rats. Quantitative RT-PCR was performed to determine growth hormone-releasing hormone (GHRH) and ghrelin mRNA expressions in GT1-7 cells. The treatment groups were administered KFB at various dosages, and the positive controls received recombinant human GH. Body weight, bone length, and density were assessed, along with serum levels of insulin-like growth factor binding protein (IGFBP)-3 and IGF-1. Results: KFB and somatropin exhibited no cytotoxic effect in GT1-7 cells and increased GHRH and ghrelin mRNA levels in a dose-dependent manner. KFB administration resulted in a significant dose-dependent increase in body weight and bone growth (femur and tibia). Changes in IGF-1 and IGFBP-3 levels were comparable to those observed in the GH-treated group. Based on network pharmacological analysis, multiple compounds in KFB ((20S)-20-hydroxypregn-4-en-3-one, 2-isopropyl-3-methoxypyrazine, caproic acid, daidzein, furfuryl alcohol, lauric acid, octanal, and salicylic acid) may synergistically regulate the PI3K-Akt, Ras, and Rap1 signaling pathways linked to growth control and cartilage formation, leading to a possible increase in height. Conclusions: Our results suggest that KFB can function as a GH-mimetic agent that promotes bone growth through IGF-1 upregulation. Full article

Orderly and controllable dissipation of impact kinetic energy is the key to ensuring train collision safety in different collision scenarios. Therefore, it is necessary to analyze the change rule of collision energy dissipation under different collision scenarios and design the parameters of the energy-absorbing structure to meet the demand for collision energy dissipation. Four representative train collision scenarios are formulated based on train collision accidents, and the concept of energy dissipation rate is proposed to characterize the drastic degree of collision energy change under different collision scenarios. Based on the train longitudinal collision dynamics model verified by the line collision test of the train, the effects of varying collision scenarios on the energy dissipation rate, energy absorption and maximum average acceleration of train collision are studied. The study results show that the longitudinal collision dynamics model of the train established in this paper can better characterize the dynamic response of the vehicle by comparing it with the results of the line collision test. The maximum difference in the speed of each vehicle after the collision is 4.91%. The differences in the energy dissipation process, interface energy absorption and maximum average acceleration are minor in four collision scenarios, including a moving train hitting a stationary train, rear-end train collision and head-on train collision. The maximum difference in energy absorbed at the interface for head-on collision is 1.54%. The initial and residual collision kinetic energy is greater in the train rear-end collision scenario, and the train rear-end collision scenario should be considered when evaluating the train’s lateral instability and vertical climbing behavior. Full article