Search Results (10,990)

Ishige okamurae Yendo (I. okamurae) is a brown macroalga with diverse biological activities. Recently, its ameliorative effects against dementia progression have been demonstrated in various in vitro and in vivo models of Alzheimer’s disease (AD), glutamate excitotoxicity, and bacterial-driven neuroinflammation. I. okamurae extract (IOE) inhibited AD progression by regulating amyloid beta–induced neuronal death and cognitive impairments. Moreover, IOE attenuated glutamate-induced neurodegeneration by modulating the mitogen-activated protein kinases/Nrf2/heme oxygenase-1 signaling pathway. Furthermore, IOE effectively suppressed lipopolysaccharide-mediated neuroinflammation and memory deficits by downregulating the Toll-like receptor 4/MyD88-dependent signaling pathway. Collectively, these findings highlight the potential of IOE as a natural multi-target, anti-dementia agent. In this review, we summarize the neuroprotective and cognition-enhancing properties of IOE, discuss the molecular mechanisms underlying its action, and consider the advantages of I. okamurae as a promising natural resource for effective therapeutic developments that are capable of targeting multiple pathogenic causes of dementia. Full article

High denitration efficiency and strong adaptability to flue gas temperature fluctuations are the core properties of the NH₃-SCR catalyst. In this study, Fe₂O₃ modification is used as a means to explore the mechanism of adding Fe₂O₃ to broaden the temperature range of the 6CeO₂-40MnO₂/TiO₂ catalyst during the preparation process. The results show that the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst exhibits excellent denitration performance, with a denitration efficiency higher than 90%. The temperature range is from 129 to 390 °C. N₂ selectivity and resistance to SO₂ and H₂O are good, and the denitration performance is significantly improved. When the Fe₂O₃ content is 6%, it promotes lattice shrinkage of TiO₂, improves its dispersion, refines the grain size, and increases the specific surface area of the catalyst. At the same time, Fe₂O₃ enhances the chemical adsorption of oxygen on the catalyst surface and increases the proportion of low-cost metal ions, thereby promoting electron transfer between active elements, generating more surface reactive oxygen species, increasing the oxygen vacancy content and adsorption sites for NO_x and NH₃, and significantly improving the redox performance of the catalyst. This effect is particularly conducive to the formation of strong acid sites on the catalyst surface. The NH₃-SCR reaction on the surface of the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst follows both the L-H and E-R mechanisms, with the L-H mechanism being dominant. Full article

Central lipid metabolism disorders are crucial for the development of Alzheimer’s disease (AD). Phlorizin (PHZ) improved lipid metabolism abnormalities in AD nematodes, but its mechanism of action in improving AD-related symptoms and whether it can alleviate AD cognitive impairment remain unclear. To elucidate the effects and mechanisms of PHZ on lipid metabolism disorders in an AD model, gavage administration of PHZ for 8 weeks improved cognitive dysfunction and lipid disorders in APPswe/PSEN1dE9 (APP/PS1) mice. Concurrently, in astrocytes induced by palmitic acid (PA)- mediated lipid metabolic disorder, PHZ treatment improved astrocytic lipid accumulation by upregulating the target peroxisome proliferator-activated receptor α (PPARα) and its downstream pathways, thereby promoting astrocytic fatty acid oxidation. We validated PHZ’s strong in vitro binding affinity with PPARα. Co-culture systems of lipid-metabolically disordered astrocytes and neurons further demonstrated that PHZ significantly improved neuronal cell viability and reduced intracellular lipid accumulation, thereby decreasing the expression of enzymes associated with β-amyloid protein (Aβ) production. This study demonstrates that gavage administration of PHZ for 2 months improves cognitive deficits and pathological markers in AD mice. Furthermore, at the cellular level, PHZ may exert its effects by enhancing astrocytic lipid metabolism, thereby preventing neuronal lipotoxicity and mitigating AD progression. Full article

Alzheimer’s disease (AD) represents a prevalent neurodegenerative disorder marked by a gradual decline in cognitive and behavioral functions. Despite advancements in elucidating several potential mechanisms underlying the pathogenesis of AD, there remains a limitation in effective supplements or medications for its intervention. Resveratrol, a natural antioxidant, has emerged as a significant player in the treatment of AD. This article reviews the role of resveratrol in four key aspects: amyloid plaque deposition and neurofibrillary tangles, inflammatory response and oxidative stress, energy metabolism and mitochondrial homeostasis, and neuroprotection and regeneration. Furthermore, we also explore treatment strategies to enhance the therapeutic effect of resveratrol. Full article

Background/Objectives: Visual dysfunction emerges during the mild cognitive impairment stage of early Alzheimer’s disease (AD). While previous studies have primarily focused on retinal pathology, the early pathological progression across central nodes of the visual pathway remains inadequately characterized. This study examined regional pathological and structural alterations throughout the visual pathway at different disease stages in APP/PS1 transgenic mice aged 3, 6, and 9 months. Methods: Cognitive function was first assessed using novel object recognition and Y-maze tests to stage disease progression. Subsequently, Histological staining was employed to systematically analyze pathological features in the retina, lateral geniculate nucleus (LGN), and primary visual cortex (V1). Evaluated parameters encompassed β-amyloid (Aβ) deposition levels, microglial activation status, total neuronal counts, parvalbumin (PV)-positive neuron numbers, and tissue thickness measurements of the retina and V1. Results: At 6 months, mice exhibited an early symptomatic phenotype with selective spatial working memory deficits while long-term memory remained intact. Pathological analysis revealed concurrent Aβ deposition and microglial activation in V1, retina, and hippocampus by 6 months, whereas comparable LGN changes manifested only at 9 months, demonstrating regional heterogeneity in disease progression. V1 neuronal populations remained stable through 6 months but showed significant reduction by 9 months, though PV-positive neurons were selectively preserved. The LGN exhibited no neuronal loss even at 9 months. Gross structural thickness of both retina and V1 remained unchanged across all timepoints. Conclusions: These findings demonstrate that early visual system pathology in this AD model extends beyond the retina. The primary visual cortex exhibits early pathological changes (Aβ deposition and neuroinflammation) concurrent with hippocampal involvement, progressing to selective neuronal loss in later stages. The severity and selectivity of V1 pathology surpass those observed in other visual pathway nodes, including the LGN. Thus, V1 could represent not merely an affected region but a promising site for elucidating early cortical AD mechanisms and developing novel diagnostic biomarkers. Full article

Radio astronomy requires precise target localization and tracking to ensure accurate observations. Conventional regulation methodologies, encompassing PID controllers, frequently encounter difficulties due to orientation inaccuracies precipitated by mechanical limitations, environmental fluctuations, and electromagnetic interferences. To tackle these obstacles, this investigation presents a reinforcement learning (RL)-oriented framework for high-accuracy monitoring in radio telescopes. The suggested system amalgamates a localization control module, a receiver, and an RL tracking agent that functions in scanning and tracking stages. The agent optimizes its policy by maximizing the signal-to-noise ratio (SNR), a critical factor in astronomical measurements. The framework employs a reconditioned 12-m radio telescope at King Mongkut’s Institute of Technology Ladkrabang (KMITL), originally constructed as a satellite earth station antenna for telecommunications and was subsequently refurbished and adapted for radio astronomy research. It incorporates dual-axis servo regulation and high-definition encoders. Real-time SNR data and streaming are supported by a HamGeek ZedBoard with an AD9361 software-defined radio (SDR). The RL agent leverages the Proximal Policy Optimization (PPO) algorithm with a self-attention actor–critic model, while hyperparameters are tuned via Optuna. Experimental results indicate strong performance, successfully maintaining stable tracking of randomly moving, non-patterned targets for over 4 continuous hours without any external tracking assistance, while achieving an SNR improvement of up to 23.5% compared with programmed TLE-based tracking during live satellite experiments with Thaicom-4. The simplicity of the framework, combined with its adaptability and ability to learn directly from environmental feedback, highlights its suitability for next-generation astronomical techniques in radio telescope surveys, radio line observations, and time-domain astronomy. These findings underscore RL’s potential to enhance telescope tracking accuracy and scalability while reducing control system complexity for dynamic astronomical applications. Full article

Clay/natural rubber (Clay–NR) nanocomposites are a sustainable material class with a wide range of applications. The type and amount of the filler added to the rubber matrix promote significant changes in the matrix properties. Montmorillonitic clays (MMT) are mineral, natural fillers. This study investigates the effect of a modified Brazilian polycationic MMT on the nanocomposite rheology and mechanical properties. The MMT was incorporated into a NR matrix in its natural state, and after modification by cation exchange (MMT^Na) and organophilization (MMT^ORG), at concentrations of 2.5 and 5 phr (parts per hundred parts of rubber). The natural and modified clays were characterized by XRD, FTIR, BET, and SEM/EDS. Mechanical tests (tensile strength, elongation at break, and modulus at 100%) indicated that the use of MMT^Na led to increased strength and modulus, whereas a minor decrease in the elongation was observed. However, the use of MMT^ORG yielded the most significant improvements in the mechanical properties. The rheology tests indicated that the Payne effect was not observed, and the strain-dependent behavior arises from matrix-dominated mechanisms, rather than disruption of a filler network. Vulcanization curves showed that the NR-MMT^ORG composites exhibited higher torque values, corroborated by higher crosslink densities. These findings highlight the critical role of cation exchange modification in optimizing MMT dispersion and interfacial interactions within NR matrices, providing design principles for high-performance sustainable nanocomposites. Full article

Geopolymer materials possess several outstanding advantages, including the wide availability of raw materials, an energy-saving and environmentally friendly production process, and excellent engineering technical performance. They are regarded as a new type of green building material that can achieve high-value-added resource utilization of industrial solid waste. They are one of the current research hotspots in the field of materials. Fly ash and slag, the most common industrial wastes in China, have been discharged in large quantities, significantly impacting the country’s ecological environment. Based on this, this paper primarily investigates the mechanical properties and strength formation mechanism of geopolymer paste to develop geopolymer materials with enhanced mechanical properties. This research uses metakaolin as the silicate raw material and uses sodium silicate mixed with NaOH as the alkali activator to prepare geopolymer paste. By adding fly ash and slag, the mechanical properties of the geopolymer paste are improved. The effects of the alkali activator modulus, Na₂O equivalent, and content of fly ash and slag on the setting time and strength of geopolymer paste are studied. XRD, FTIR, and SEM are employed to characterize the phase, molecular structure, and microscopic morphology of geopolymer paste, as well as to analyze the microstructure and reaction mechanism of these materials. The results show that the setting time of the geopolymer increases with the increase in modulus and shortens with the increase in Na₂O equivalent. Fly ash and slag, respectively, act as retarders and early strength promoters. The ratio of n(SiO₂)/n(A1₂O₃) (that is, the modulus of the alkali activator) of the geopolymer is an important factor affecting its strength. The metakaolin and fly ash–slag–metakaolin exhibit the best mechanical properties when their molar ratios are 2.97 and 3.26, respectively. Through microscopic characterization using XRD, FTIR, and SEM, it is observed that fly ash–slag–metakaolin exhibits the most complete polymerization reaction, generates the most amorphous silicate aluminosilicate gel, and displays the best inter-gel bonding effect, resulting in the best mechanical properties. Full article

The current global economic challenges and resource scarcity necessitate the development of cost-effective and sustainable pavement solutions. This study investigates the performance of asphalt mixtures modified with Low-Density Polyethylene (LDPE) and Styrene–Butadiene–Styrene (SBS) as binder modifiers, and Hydrated Lime (Ca(OH)₂) and Reclaimed Asphalt Pavement (RAP) as aggregate replacements. The research aims to optimize the combination of these materials for enhancing the durability, sustainability, and mechanical properties of asphalt mixtures under various climatic and traffic conditions. Asphalt mixtures were modified with 5% LDPE and 2–6% SBS (by bitumen weight), with 2% Hydrated Lime and 15% RAP added to the mix. The performance of these mixtures was evaluated using the Simple Performance Tester (SPT), focusing on rutting, cracking, and fatigue resistance at varying temperatures and loading frequencies. The NCHRP 09-29 Master Solver was employed to generate master curves for input into the AASHTOWare Mechanistic-Empirical Pavement Design Guide (MEPDG), allowing for an in-depth analysis of the modified mixes under different traffic and climatic conditions. Results indicated that the mix containing 5% LDPE, 2% SBS, 2% Hydrated Lime, and 15% RAP achieved the best performance, reducing rutting, fatigue cracking, and the International Roughness Index (IRI), and improving overall pavement durability. The combination of these modifiers showed enhanced moisture resistance, high-temperature rutting resistance, and improved dynamic modulus. Notably, the study revealed that in warm climates, thicker pavements with this optimal mix exhibited reduced permanent deformation and better fatigue resistance, while in cold climates, the inclusion of 2% SBS further improved the mix’s low-temperature performance. The findings suggest that the incorporation of LDPE, SBS, Hydrated Lime, and RAP offers a sustainable and cost-effective solution for improving the mechanical properties and lifespan of asphalt pavements. Full article

Terrain referenced navigation (TRN) determines position by comparing terrain height measurements with digital elevation maps (DEMs). However, terrain fluctuations create multimodal observation distributions, introducing significant nonlinearity that challenges fusion positioning algorithms. To address this, we propose a novel data fusion approach: batch cyclic posterior selection particle filter (BCPS-PF), applied to TRN. Our algorithm consists of two primary mechanisms. First, the batch cycle particle generation mechanism continuously generates particles conforming to the prior distribution. This is achieved by decomposing the state transition function and the state noise model during the prediction step. Particles from the previous time step are transformed via the state transition function, and noise sequences generated by the state noise model are added, forming batch cycle particles. Second, a particle selection mechanism filters particles to match the posterior distribution. This involves an update step in the fusion process, utilizing a rejection sampling technique. The batch cycle mechanism can be terminated by limiting the number of particles, and state estimation is derived by calculating the mean of these particles. Simulations demonstrate that our method improves positioning accuracy by over 10% compared with existing methods. Full article

Background/Objectives: Oxidative stress is a central mechanism in the pathogenesis of cirrhosis, yet its clinical significance relative to established predictors remains unclear. Methods: We conducted a retrospective cohort study of 90 patients with cirrhosis hospitalized between October 2024 and March 2025. Clinical data, biochemical parameters, systemic inflammatory indices, and oxidative stress markers [malondialdehyde (MDA), 8-epi-prostaglandin F2α (8-epi-PGF2α)] were assessed at admission. Statistical analyses included non-parametric group comparisons, Spearman correlations, logistic regression with interaction terms, ROC analysis with bootstrap confidence intervals, model calibration and discrimination metrics, reclassification indices (NRI, IDI), and decision curve analysis (DCA). Results: Patients with advanced encephalopathy (HE3) had significantly higher MDA levels compared with HE1 (123.4 [107.6–248.4] vs. 131.0 [66.9–301.1] ng/mL; p = 0.021), while 8-epi-PGF2α showed a non-significant but consistent trend. Both oxidative markers correlated with biochemical dysfunction (MDA with INR and albumin; 8-epi-PGF2α with direct bilirubin). ROC analyses demonstrated modest discriminative ability (AUC 0.55–0.60) compared with albumin (AUC 0.74–0.90) and INR (AUC 0.72–0.88). In regression models, albumin remained the strongest independent predictor, whereas oxidative markers did not retain significance. Interaction models suggested that oxidative stress exerted context-dependent effects, particularly in patients with elevated inflammatory indices. Incremental predictive value beyond age and albumin was minimal (ΔAUC ≤ 0.01; NRI + 2–4%). DCA confirmed no added clinical utility. Conclusions: Classical clinical markers, particularly albumin and INR, dominate predictive accuracy in cirrhosis. Oxidative stress markers lack independent predictive power but consistently associate with worsening encephalopathy and liver dysfunction, underscoring their biological relevance and suggesting their role is best understood in conjunction with systemic inflammation. Full article

As attention to environmental risks from the PAHs in biochar production increases, developing a low-cost and easy-to-operate optimized pyrolysis process is urgent. The effect of extra biochar was investigated in order to minimize polycyclic aromatic hydrocarbons (PAHs) on biochar and residual tar for the development of a new fixed-bed pyrolysis process. Hence, the effect of extra biochar as a catalyst on the reduction effect on PAHs originating from corn stover pyrolysis was inspected and explored in this study. Pyrolysis was conducted at 500, 600, and 700 °C in a tube furnace reactor with corn stover as the biomass feedstock. Biochar prepared at 500 °C, 600 °C, and 700 °C was used as a catalyst by stacking extra biochar on top of the corn stover raw material. Then, the concentration of PAHs in corn stover biochar and residual tar inside the reactor was examined. The physicochemical characteristics, including morphology, pore structure, and chemical structures of extra biochar, were investigated separately. The results showed that, with stacking extra biochar, the concentrations of PAHs in corn stover biochar (7.15 mg/kg to 1.25 mg/kg) and residual tar (132.23 mg/kg to 101.10 mg/kg) inside the reactor decreased significantly at medium temperatures (500 °C). The concentrations of PAHs in corn stover biochar decreased from 9.14 mg/kg, 10.44 mg/kg to 3.66 mg/kg, 2.7 mg/kg. However, the concentrations of PAHs of residual tar inside the reactor increased significantly at medium temperatures (600 °C, 700 °C). In addition, the reaction mechanism of extra biochar as a catalyst to reduce PAHs in corn stover biochar was established. The results suggest that the measure of adding extra biochar reduced PAHs in resulting biochar effectively, but is not high enough to eliminate PAHs issues in the entire pyrolysis process completely. Full article

Biodegradable alloys are increasingly studied in medical research to find the best balance between mechanical performance and biocompatibility. Magnesium (Mg) alloys are particularly attractive because of their low density, good mechanical properties, and compatibility with the human body. However, rapid corrosion limits their wider use. Recently, Mg alloys containing zinc (Zn) and calcium (Ca) have drawn interest due to more suitable degradation rates. In this study, Mg₆₆Zn₃₀Ca₄ was chosen as the base alloy due to its high mechanical strength, excellent biocompatibility, and favorable corrosion behavior, making it an ideal starting point for biodegradable implants. We investigated how adding ytterbium (Yb) affects the mechanical and corrosion behavior of this base alloy. Mg_66−xZn₃₀Ca₄Yb_x (x = 2, 4, 6) rods were produced using rapid solidification, and their mechanical and electrochemical properties were systematically evaluated. The results show that adding Yb significantly improves corrosion resistance while maintaining high mechanical strength, making these materials promising for applications requiring both strength and controlled degradation. Corrosion tests indicated that the surface of the samples developed an oxygen-rich layer approximately 18 μm thick, as identified by EDS mapping. Overall, Yb modification enhances the suitability of Mg-Zn-Ca alloys for biodegradable orthopedic implants. Full article

The development of advanced wound dressings that integrate favorable physico-mechanical properties with the ability to support physiological healing processes remains a critical challenge in biomaterials science. An ideal dressing should modulate the wound microenvironment, prevent infection, maintain hydration, and possess adequate strength and elasticity. This study aimed to fabricate and characterize electrospun chitosan (CS)-based 3D scaffolds dual-reinforced with halloysite nanotubes (HNTs) and cerium oxide nanoparticles (CeONPs) to enhance material properties and biological performance. HNTs were incorporated to improve electrospinnability and provide mechanical reinforcement, while CeONPs were added for their redox-modulating and anti-inflammatory activities. Composite mats were fabricated via non-capillary electrospinning. The individual and synergistic effects of HNTs and CeONPs were systematically evaluated using physico-chemical methods (SEM, EDX, WAXS, TGA, mechanical testing) and biological assays (in vitro cytocompatibility with mesenchymal stem cells, in vivo biocompatibility, and wound healing efficacy in a rat model). Scaffolds containing only HNTs exhibited defect-free nanofibers with an average diameter of 151 nm, whereas the dual-filler (CS-PEO-HNT-CeONP) composites showed less uniform fibers with a rough surface and a larger average diameter of 233 nm. The dual-filler system demonstrated significantly enhanced mechanical properties, with a Young’s modulus nearly double that of pure CS mats (881 MPa vs. 455 MPa), attributed to strong interfacial interactions. In vivo, the CS-PEO-HNT-CeONP scaffolds degraded more slowly, promoted earlier formation of a connective tissue capsule, and elicited a reduced inflammatory response compared to single-filler systems. Although epithelialization was temporarily delayed, the dual-filler composite ultimately facilitated superior tissue regeneration, characterized by a more organized, native-like collagen architecture. The synergistic combination of HNTs and CeONPs within a CS matrix yields a highly promising scaffold for wound management, offering a unique blend of tailored biodegradability, enhanced mechanical strength, and the ability to guide healing towards a regenerative rather than a fibrotic outcome, particularly for burns and traumatic injuries. Full article

In this paper, a hybrid locomotion approach is proposed and experimentally validated for a quadrupedal robot to enhance energy efficiency on mixed terrains. A mechanical solution was implemented by adding passive wheels on the robot’s abdomen, to allow for gliding on flat portions of the faced terrains. This strategy aims to reduce the use of the legs, decreasing the overall energy consumption. To allow an efficient use of simulations, a data-driven approach was developed to estimate motor power consumption from joint dynamics on the real robot and subsequently applied within the simulation environment. The neural network achieved a coefficient of determination of R² = 0.97, ensuring accurate estimation of energy consumption under both simulated and real conditions. Experimental and simulated results show that the proposed sliding gait reduces the average Cost of Transport from approximately 4.5–6.0 during trotting to 0.8–1.1 during sliding, corresponding to a four–five-fold improvement in energy efficiency. Overall, the results demonstrate that a simple mechanical upgrade of the robot’s body structure can significantly enhance locomotion efficiency and versatility on flat or slightly descending terrains. Full article