Search Results (910)

A wide experimental campaign was developed on an automotive turbocharged diesel engine, using two blends between diesel oil and waste cooking oil methyl esters (WCOME) and neat biodiesel. A conventional B7 diesel oil was considered as a reference fuel. The two blends, respectively, included 40 and 70% of WCOME, on a volumetric basis. The influence of biodiesel was analyzed by testing the engine in two part-load operating conditions, applying proper control strategies to the exhaust gas recirculation (EGR) circuit and rail pressure, to assess the interactions between the engine management and the tested fuels. The variable nozzle turbine (VNT) was controlled to obtain a constant level of intake pressure in the two experimental points. Referring to biodiesel effects at constant operating mode, higher WCOME content generally resulted in better efficiency and soot emission, while NO_X emission was negatively affected. EGR activation allowed for limited NO formation but with penalties in soot emission. Furthermore, interactions between the EGR circuit and turbocharger operations and control led to higher fuel consumption and lower efficiency. Finally, the increase in rail pressure corresponded to better soot emission and penalties in NO_X emission. Combining all these effects, the selection of EGR rate and rail pressure values higher than the standard levels resulted in better efficiency, NO_X, and soot emissions when comparing blends and neat biodiesel to conventional B7, granting advantages not only with regard to greenhouse gas emissions. Combustion parameters were also assessed, showing that combustion stability and combustion noise were not negatively affected by biodiesel use. Combustion duration was reduced when using WCOME and its blend, even if the center of combustion was slightly shifted along the expansion stroke. The main contribution of this investigation to the scientific and technical knowledge on biodiesel application to internal combustion engines is related to the development of tests on diesel–biodiesel blends with high WCOME content or neat WCOME, identifying their effects on NO_X emissions, the definition of integrated strategies of HP EGR system, fuel rail pressure, and VNT for the simultaneous reduction in NO_X and soot emissions, and the detailed assessment of the influence of biodiesel on a wide range of combustion parameters. Full article

Ischemic stroke is the most common type of stroke and poses a major global health challenge due to its high mortality and lasting disability impact. The onset and progression of ischemic stroke are largely linked to oxidative stress and inflammatory responses. Alpinetin, a natural flavonoid found in the ginger family, exhibits various pharmacological properties, including antioxidant and anti-inflammatory activities. In this study, the neuroprotective potential of alpinetin in attenuating oxidative stress and inflammation against cerebral ischemic stroke was evaluated. Ninety male Wistar rats were randomly assigned to the sham operation group, the Rt.MCAO group, the Rt.MCAO+piracetam group, and the Rt.MCAO+alpinetin groups (25, 50, and 100 mg/kg BW). Cerebral infarction size, neuronal density, and antioxidant and anti-inflammatory activities were measured. Three days of treatment with alpinetin markedly reduced the infarct volume by 30% compared to the Rt.MCAO+vehicle-treated group. Additionally, rats treated with alpinetin exhibited a significant increase in neuronal density in the cortex, as well as in the CA1 and CA3 regions of the hippocampus. Furthermore, treatment with alpinetin ameliorated both the Rt.MCAO-induced increase in malondialdehyde (MDA) activity and the Rt.MCAO-induced decrease in catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activities in the cortex and hippocampus. Moreover, COX-2 and IL-6 protein levels were assessed using western blotting. The results showed that treatment with alpinetin (100 mg/kg BW) significantly reduced the expression levels of COX-2 and IL-6 in both the cortex and hippocampus. Our findings suggest that alpinetin significantly mitigates the effects of cerebral ischemia-induced brain damage through its antioxidant and anti-inflammatory properties and could potentially be developed as a therapeutic agent for stroke treatment. Full article

With the enhancement of safety performance requirements in the car manufacturing field, the quality standards for the sheet molding process have imposed higher demands. However, during the pressure-building phase of pump-controlled hydraulic die cushion systems, the combined effects of high-order dynamics, system uncertainties, and strong nonlinearities pose significant challenges to maintaining precise control and dynamic response performance of the blank holder force (BHF). To address these challenges, we propose an intelligent model predictive control (MPC) strategy that synergistically integrates an extended state observer (ESO) for disturbance compensation with parameters optimized by a genetic algorithm (GA). The mathematical model and state-space model of the system are established. Subsequently, the ESO is integrated with MPC to enable active compensation for internal and external disturbances. The GA is employed to optimize the controller parameters within the MPC framework. Finally, a simulation testbed for the pump-controlled hydraulic die cushion experimentally validates the process. Experimental results demonstrate that compared to MPC and conventional PID control, the proposed strategy achieves significant reductions in pressure overshoot (0.87% and 1.8% at 100 bar; 3.3% and 5.9% at 200 bar), pressure-building time (13.9% and 31.4% at 100 bar; 6.7% and 11.5% at 200 bar), and stroke length (10.5% and 32% at 100 bar; 11.5% and 28.1% at 200 bar). This validates its effectiveness in enhancing both control precision and dynamic response performance, providing a reliable solution for large-scale applications of pump-controlled hydraulic die cushions in high-dynamic stamping scenarios. Full article

Background/Objectives: Individuals with chronic stroke often experience various impairments, including poor balance, reduced mobility, limited physical activity, and difficulty performing daily tasks. In the context of the COVID-19 pandemic, telerehabilitation (TR) can overcome the barriers of geographical and physical distancing, time, costs, and travel, as well as the anxiety about contracting COVID-19. In this retrospective case-control study, we aim to evaluate the motor and cognitive effects of balance TR training carried out with a sensor-based non-immersive virtual reality system compared to conventional rehabilitation in chronic stroke patients. Methods: Twenty chronic post-stroke patients underwent evaluation for inclusion in the analysis through an electronic recovery data system. The patients included in the study were divided into two groups with similar medical characteristics and duration of rehabilitation training. However, the groups differed in the type of rehabilitation approach used. The experimental group (EG) received TR with a sensor-based VR device, called VRRS—HomeKit (n. 10). In contrast, the control group (CG) underwent conventional home-based rehabilitation (n. 10). Results: At the end of the training, we observed significant improvements in the EG in the 10-m walking test (10MWT) (p = 0.01), Timed-Up-Go Left (TUG L) (p = 0.01), and Montreal Cognitive Assessment (MoCA) (p = 0.005). Conclusions: In our study, we highlighted the potential role of sensor-based virtual reality TR in chronic stroke patients for improving lower limb function, suggesting that this approach is feasible and not inferior to conventional home-based rehabilitation. Full article

This study introduces a novel magnetorheological (MR) damper for semi-active vehicle suspension systems that enhance ride comfort and handling stability. The proposed damper integrates reverse and normal damping modes, enabling independent control of rebound and compression strokes through an external MR valve. This configuration supports four damping modes—Soft/Soft, Hard/Soft, Soft/Hard, and Hard/Hard—allowing adaptability to varying driving conditions. Magnetic circuit optimization ensures rapid damping force adjustments (≈10 ms), while a semi-active control algorithm incorporating skyhook logic, roll, dive, and squat control strategies was implemented. Experimental validation on a mid-sized sedan demonstrated significant improvements, including a 30–40% reduction in vertical acceleration and pitch/roll rates. These enhancements improve vehicle safety by reducing body motion during critical maneuvers, potentially lowering accident risk and driver fatigue. In addition to performance gains, the simplified MR damper architecture and modular control facilitate easier integration into diverse vehicle platforms, potentially streamlining vehicle design and manufacturing processes and enabling cost-effective adoption in mass-market applications. These findings highlight the potential of MR dampers to support next-generation vehicle architectures with enhanced adaptability and manufacturability. Full article

Neurological disorders like stroke are one of the main causes of motor dysfunction and gait function disabilities in humans. These disorders impact the mobility of patients often leading to weakened and impaired ankle joints which further compromise their balance and walking abilities. Over the span of the last twenty years, there has been a rising interest in designing, developing, and using rehabilitative robots for patients suffering from various ankle joint disabilities. These robotic devices are developed by employing diverse mechanical designs, materials, and control strategies. The aim of this study is to provide a detailed overview of the recent developments in mechanical design, actuation, and control strategies of ankle rehabilitation robots. Experimental evaluation of the discussed ankle robots has also been carried out discussing their results and limitations. This article concludes by highlighting future challenges and opportunities for the advancement of ankle rehabilitation robots, stressing the need for robust and effective devices to better serve patients. Full article

Background: Early studies indicated that the high content of tanshinone IIA (T−IIA) and rosmarinic acid (RA) in Salvia castanea Diels f. Tomentosa Stib (SCT) gives them significant potential for development as therapeutic agents for ischemic stroke (IS). However, the extraction process and quality of the active ingredients from SCT are still big challenges, with present processes providing insufficient pharmacological effects. This study aims to identify the optimal extraction process and perform a quality characterization of the total tanshinones and phenolic acids extracted from SCT, as well as to elucidate the neuroprotective effect of these extracts. Methods: The extraction process was optimized using an orthogonal experimental design (OED), and quality characterization was performed using HPLC, UV, and LC-MS. The neuroprotective effect of the extracted tanshinones and phenolic acids was studied using the middle cerebral artery occlusion (MCAO) paradigm, and its underlying mechanism was revealed through RNA-seq analysis combined with network pharmacology. Results: The optimal extraction pressure of total tanshinones was 60 MPa, while the extraction temperature and time for total phenolic acids were 4 °C and 25 min, respectively. In these extracts, the total tanshinone and phenolic acid contents increased to 369.43 and 189.10 mg/g, respectively; 23 of the 19 tanshinones and 23 phenolic acids identified in this study have not been observed in previous studies. It was demonstrated that the combined extract had a promising neuroprotective effect against IS; RNA-seq combined with network pharmacology analysis indicated that the active compounds may regulate a series of core genes associated with signaling pathways to protect against IS. Conclusions: The combined SCT extract studied in this research exerted neuroprotective effects on IS. In general, these findings improve our preliminary understanding of the chemical composition and bioactivity of SCT. Full article

Methanol, a renewable and sustainable fuel, provides an effective strategy for reducing greenhouse gas emissions when synthesized through carbon dioxide hydrogenation integrated with carbon capture technology. The incorporation of hydrogen into methanol-fueled engines enhances combustion efficiency, mitigating challenges such as pronounced cycle-to-cycle variations and cold-start difficulties. A simulation framework was developed using Python 3.13 and the Cantera 3.1.0 library to model the combustion system of a four-stroke spark-ignited (SI) methanol–hydrogen engine. This framework integrates a fractal turbulent combustion model with chemical reaction kinetics, complemented by early flame development and near-wall combustion models to address limitations during the initial and terminal combustion phases. The model was validated by using experimental data measured from a spark-ignited methanol engine. The effects of varying Hydrogen Energy Rates (HER) on engine power performance, combustion characteristics, and emissions (like formaldehyde and carbon monoxide) were subsequently analyzed under different operating loads, whilst the knock limit boundaries were established for different operational conditions. Findings demonstrate that increasing HER improves the engine power output and thermal efficiency, shortens the combustion duration, and reduces the formaldehyde and carbon monoxide emissions. Nevertheless, under high-load conditions, higher HER increases the knocking tendency, which constrains the maximum permissible HER decreasing from approximately 40% at 15% load to 20% at 100% load. The model has been developed into a Python library and will be open-sourced on Github. Full article

The highly conserved Wnt signaling pathway, a complex network critical for embryonic development and adult tissue homeostasis, regulates diverse cellular processes, ultimately influencing tissue organization and organogenesis; its dysregulation is implicated in numerous diseases, and it is known to be affected by oxidative pathways. This report reviews the recent literature on major classes of natural products with pronounced anti-oxidant properties, such as cardiac glycosides, steroid saponins, ecdysteroids, withanolides, cucurbitacins, triterpenes, flavonoids, and iridoids, that modulate its activity in various pathological conditions, summarizing and critically analyzing their effects on the Wnt pathway in various therapeutically relevant experimental models and highlighting the role of ROS-mediated crosstalk with Wnt signaling in these studies. Models reviewed include not only cancer but also stroke, ischemia, bone or kidney diseases, and regenerative medicine, such as re-epithelialization, cardiac maintenance, and hair loss. It highlights the paramount importance of modulating this signaling by natural products to define future research directions. We also discuss controversies identified in the mode of action of several compounds in different models and directions on how to further improve the quality and depth of such studies. Full article

There is increasing interest in identifying drugs that can prevent or delay neurological complications following spinal cord injury, thus expanding the therapeutic window for other potential neuroprotective agents. In this context, manganese porphyrins (MnPs) have shown high antioxidant and anti-inflammatory potential in various experimental disease models, including stroke, cancer, diabetes, ischemia, and radiotherapy. However, they have been little evaluated in spinal cord injuries. This study aimed to assess the therapeutic potential of the manganese porphyrins [MnTE-2-PyP]⁵⁺ (MnPI) and [MnT(5-Br-3-E-Py)P]⁵⁺ (MnPII) in acute compressive spinal cord trauma in rats. Twenty-four animals were used (six animals/group). Following general inhalation anesthesia, acute compressive spinal cord trauma was induced in all groups except for the negative control (SHAM). Treatment commenced 60 min post-trauma, with animals receiving treatment for seven days at 24 h intervals. While no improvement in motor capacity was observed, MnPs effectively blocked the increase in oxidative stress and endoplasmic reticulum (ER) stress mediators caused by trauma, maintaining the protein expression levels of Hifα, 8-OHdG and MDA, as well as the expression of the genes Grp78, Chop, Ho1, and Perk, similar to those of the control group. Moreover, there was an increase in protein expression of SOD1, Cat, and GPX1, along with a restoration of SOD and CAT enzymatic activity. Additionally, MnPs improved the expression of IL-6, neurotrophic markers, and apoptotic factors. In conclusion, treatment with MnPs attenuated the oxidative stress and ER stress caused by acute compressive spinal cord trauma and restored spinal expression of neurotrophic mediators. Full article

Clinical research has demonstrated that stroke patients benefit from active participation during robot-assisted training. However, the weight of the arm impedes the execution of tasks and movements due to the functional disability. The purpose of this paper is to develop a gravity compensation strategy for an end-effector upper limb rehabilitation robot based on an arm dynamics model to reduce the arm’s muscle activation level. This control strategy enables real-time evaluation of arm gravity torques based on feedback from upper limb kinematic parameters. The performance of the proposed strategy in movement tracking is then compared to that of other types of weight compensation strategies. Experimental results demonstrate that compared to movements without compensation, the mean activation levels of arm muscles with the proposed strategy showed a significant reduction (p < 0.05), except for activation of the triceps. Furthermore, the proposed strategy provides superior performance in reducing the arm muscle’s effort compared to the position-varying weight compensation strategy. Therefore, with the proposed strategy, the end-effector rehabilitation robot might improve participation in robot-assisted rehabilitation training, as well as the usability and feasibility of the rehabilitation or assistive robot. Full article

Bionic micro air vehicles are currently being popularized for military as well as civilian use and dragonflies display a wealth of skill in their remarkable flight capabilities. This study designs an asymmetric motion flapping-wing mechanism inspired by the dragonfly, using a single actuator to achieve the coupling of stroke and pitch motion. This study simulates the motion of the dragonfly’s wings using the designed mechanism and experimentally validates the motion laws and aerodynamic characteristics of the mechanism. The analysis focuses on the asymmetry in the wing’s stroke and pitch motion and their aerodynamic implications. The flapping-wing mechanism accurately replicates the wing motion of a real dragonfly in flight, and the maximum lift-to-weight ratio can reach up to 230.2%, demonstrating significant aerodynamic benefits. This mechanism provides valuable guidance for the structural design and kinematic control of future flapping-wing vehicles. Full article

Background: Gait and balance alterations in post-stroke patients are one of the most disabling symptoms that can persist in chronic stages of the disease. In this context, rehabilitation has the fundamental role of promoting functional recovery, mitigating gait and balance deficits, and preventing falling risk. Robotic end-effector devices, like the G-EO system (e.g., G-EO system, Reha Technology, Olten, Switzerland), can be a useful device to promote gait recovery in patients with chronic stroke. Materials and Methods: Twelve chronic stroke patients were enrolled and evaluated at baseline (T0) and at post-treatment (T1). These patients received forty sessions of robotic gait training (RGT) with the G-EO system (experimental group, EG), for eight weeks consecutively, in addition to standard rehabilitation therapy. The data of these subjects were compared with those coming from a sample of twelve individuals (control group, CG) matched for clinical and demographic features who underwent the same amount of conventional gait training (CGT), in addition to standard rehabilitation therapy. Results: All patients completed the trial, and none reported any side effects either during or following the training. The EG showed significant improvements in balance (p = 0.012) and gait (p = 0.004) functions measured with the Tinetti Scale (TS) after RGT. Both groups (EG and CG) showed significant improvement in functional independence (FIM, p < 0.001). The Fugl-Meyer Assessment—Lower Extremity (FMA-LE) showed significant improvements in motor function (p = 0.001, p = 0.031) and passive range of motion (p = 0.031) in EG. In EG, gait and balance improvements were influenced by session, age, gender, time since injury (TSI), cadence, and velocity (p < 0.05), while CG showed fewer significant effects, mainly for age, TSI, and session. EG showed significantly greater improvements than CG in balance (p = 0.003) and gait (p = 0.05) based on the TS. Conclusions: RGT with end-effectors, like the G-EO system, can be a valuable complementary treatment in neurorehabilitation, even for chronic stroke patients. Our findings suggest that RGT may improve gait, balance, and lower limb motor functions, enhancing motor control and coordination. Full article

This paper presents an experimental study of uniform and variable texture patterns on a honed EN-GJS 400-15 spheroidal graphite cast iron surface. Textured samples were fabricated using a CNC electrochemical jet machining technique and tested against a 52100 G5 roller countersurface featuring a rectangular 1 mm × 13 mm contact area. Tribological tests were conducted in a fully flooded PAO4 lubricant bath at 30 °C on a TE-77 reciprocating sliding tribometer with a 25 mm stroke length. Frictional behaviour was assessed at test frequencies from 12 to 18 Hz under two loads, 11 N and 50 N, covering mixed and hydrodynamic lubrication regimes. Experimental results demonstrated that EJM textured surfaces were accurately fabricated within a ±2.50 µm standard error in depth, with chemical etching effects reducing the $R_q$ roughness of initial grinding marks by 0.223 µm. Textured surfaces exhibited a more pronounced friction performance at 50 N than at 11 N, exhibiting a consistent friction reduction of up to 18.8% compared to the untextured surface. The variable textured surface outperformed the uniform textured surface under the mixed lubrication regime due to the enhanced secondary lubrication effect. Optical and SEM analyses revealed that textured surfaces reduced plastic deformation and two-body abrasion. Full article

Ischaemic stroke is the most prevalent stroke subtype, accounting for 80–90% of all cases worldwide, and remains a leading cause of morbidity and mortality. Its pathophysiology involves complex molecular cascades, with oxidative stress playing a central role. During cerebral ischaemia, reduced blood flow deprives neurons of essential oxygen and nutrients, triggering excitotoxicity, mitochondrial dysfunction, and excessive production of reactive oxygen and nitrogen species (RONS). Not only do these species damage cellular components, but they also activate inflammatory pathways, particularly those mediated by the transcription factor nuclear factor kappa-B (NF-κB). The pro-inflammatory milieu intensifies neuronal damage, compromises blood–brain barrier integrity, and exacerbates reperfusion-induced damage. Recent findings highlight the importance of the gut microbiota in modulating stroke outcomes, primarily through metabolic and immunological interactions along the gut–brain axis. Dysbiosis, characterised by reduced microbial diversity and an imbalance between beneficial and harmful strains, has been linked to increased systemic inflammation, oxidative stress, and worse prognoses. Specific gut-derived metabolites, including short-chain fatty acids (SCFAs) and trimethylamine N-oxide (TMAO), appear to either mitigate or intensify neuronal injury. SCFAs may strengthen the blood–brain barrier and temper inflammatory responses, whereas elevated TMAO levels may increase thrombotic risk. This narrative review consolidates both experimental and clinical data demonstrating the central role of oxidative stress in ischaemic stroke pathophysiology and explores the gut microbiota’s ability to modulate these damaging processes. Therapeutic strategies targeting oxidative pathways or rebalancing gut microbial composition, such as antioxidant supplementation, dietary modulation, probiotics, and faecal microbiota transplantation, present promising paradigms for stroke intervention. However, their widespread clinical implementation is hindered by a lack of large-scale, randomised trials. Future efforts should employ a multidisciplinary approach to elucidate the intricate mechanisms linking oxidative stress and gut dysbiosis to ischaemic stroke, thereby paving the way for novel, mechanism-based therapies for improved patient outcomes. Full article