Search Results (62)

The present contribution showcases the potential brake emission reduction with Cr₂O₃ (chromium oxide) and WC-CoCr (tungsten carbide–chromium–cobalt) rotor coatings, as realized in our joint public–private research consortium. Particulate matter (PM) emissions from automotive braking systems have been characterized using a pin-on-disc tribometer equipped with particle measurement devices: a CPC (Condensation Particle Counter), an APS (Aerodynamic Particle Sizer), an SMPS (Scanning Mobility Particle Sizer), and a PM_2.5 sampling unit. Brake pad samples made from the same low-steel friction material were tested against a grey flake cast iron disc and two types of custom coated discs: a Cr₂O₃-coated disc and a WC-CoCr-coated disc. The friction pairs were investigated at a constant contact pressure of 1.2 MPa while the sliding velocity varied during the test, starting with 25 sequences at 3.6 m/s, followed by 19 sequences at 6.1 m/s, and finishing with 6 sequences at 11.2 m/s. The test results show encouraging 64% to 84% reductions in particle number (PN) emissions between 4 nm and 3 µm and 84% to 95% reductions in mass emissions (PM_2.5) thanks to the respective coated discs. SEM-EDXS (Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy) analyses show that the hardness and roughness of the discs, the chemical reactivity (oxidation), and the abrasiveness of the three friction pairs are parameters that might explain this reduction in emission. Full article

Background/Objectives: Osteoarthritis (OA) is a complex joint disease involving chronic inflammation, aging, and obesity, affecting nearly 6 million people worldwide. Senescent cells in OA are linked to increased inflammation, oxidative stress, and DNA damage, making them potential therapeutic targets. APPA, a combination of apocynin (AP) and paeonol (PA), has shown anti-inflammatory and antioxidant properties. This study evaluated the effects of APPA on cellular senescence in human articular chondrocytes. Methods: Using a chondrocyte cell line (T/C-28a2) and primary human chondrocytes, senescence was induced with etoposide and Oncostatin M (Eto + OSM), followed by treatment with APPA, AP, or PA. Senescence markers (SA-β-gal, P21_CDKN1A_), apoptosis, proliferation (Ki67), and rps6 protein levels were analyzed. Results: APPA significantly reduced SA-β-gal activity and p21 expression in cell model—effects not replicated by AP or PA alone. APPA increased early apoptosis and dual-labeled senescent-apoptotic cells, along with total cell numbers and rps6 levels. It also altered Ki67 expression in different cell subpopulations, suggesting effects on proliferation. Conclusions: This study suggests that APPA exerts senotherapeutic effects on human senescent chondrocytes. A reduction in SA-β-gal together with an increase in cell numbers and the proliferation marker Ki67 suggests possible senomorphic effects, whereas a reduction in SA-β-Gal accompanied by an increase in apoptosis indicates senolytic activity. These findings support recent evidence that the distinction between senolytic and senomorphic agents is ‘fuzzy’. Full article

Tool structure design methodologies predominantly rely on trial-and-error approaches or single-objective optimization but fail to achieve coordinated enhancement of multiple performance metrics while lacking thorough investigation into complex cutting coupling mechanisms. This study proposes a multi-objective optimization framework integrating joint simulation approaches. First, a finite element model for orthogonal turning was developed, incorporating the hyperbolic tangent (TANH) constitutive model and variable coefficient friction model. The cutting performance of four micro-groove configurations is comparatively analyzed. Subsequently, parametric modeling coupled with simulation–data interaction enables multi-objective optimization targeting minimized cutting force, reduced cutting temperature, and decreased wear rate. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) explores Pareto-optimized solutions for arc micro-groove geometric parameters. Finally, optimized tools manufactured via powder metallurgy undergo experimental validation. The results demonstrate that the optimized tool achieves significant improvements: a 19.3% reduction in cutting force, a 14.2% decrease in cutting temperature, and tool life extended by 33.3% compared to baseline tools. Enhanced chip control is evidenced by an 11.4% reduction in chip curl radius, accompanied by diminished oxidation/adhesive wear and superior surface finish. This multi-objective optimization methodology effectively overcomes the constraints of conventional single-parameter optimization, substantially improving comprehensive tool performance while establishing a reference paradigm for cutting tool design under complex operational conditions. Full article

The co-electrolysis of nitrate and CO₂ can contribute to urea production with low carbon-oxide emission rate and at the same time reduce NO₃⁻ to extremely low permissible concentrations. It was found that Ag and Fe particles, as thin catalytic layers, can potentially be used for the joint reduction of NO₃⁻ and CO₂ under benign ambient conditions. The linear voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and electron scanning microscopy were used. The Fe/C electrocatalyst exhibits superior current density stability at −1.2 V vs. Ag/AgCl, whereas Ag/C electrocatalyst shows noticeable degradation over time. This reaction is necessary both for the removal of nitrates from wastewater and for the capture of carbon dioxide, which makes it one of the important applications of sustainable chemistry. Full article

Walnut (Juglans regia L.), an ecologically and economically important species, requires the elucidation of its salt stress response mechanisms for improved salt tolerance breeding. This study elucidates the physiological and molecular mechanisms through which exogenous methyl jasmonate (MeJA) mitigates salt stress in walnut, providing novel strategies for salt-tolerant cultivar development. This integrated study combined physiological, biochemical, and multi-omics analyses to decipher how exogenous MeJA enhances ROS scavenging through the synergistic activation of phenylalanine (Phe), tryptophan (Trp), and α-linolenic acid pathways, establishing a multilevel antioxidant defense network. MeJA treatment effectively mitigated salt stress-induced oxidative damage, as demonstrated by a significant 16.83% reduction in malondialdehyde (MDA) content, concurrent 11.60%, 10.73% and 22.25% increases in superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, respectively, the elevation of osmoregulatory soluble sugars (SS), and 1.2- to 2.0-fold upregulation of key antioxidant enzyme genes (SOD, POD, APX, GPX, DHAR) and elevated osmoregulatory substances (soluble sugars, SS). Improved photosynthetic parameters (P_n, G_s) and chlorophyll fluorescence efficiency (F_v/F_m) collectively indicated reduced oxidative stress (improved by 7.97–23.71%). Joint metabolomic-transcriptomic analyses revealed MeJA-enhanced ROS scavenging via the coordinated regulation of Phe, Trp, and α-linolenic acid pathways. In summary, MeJA significantly enhanced reactive oxygen species (ROS) scavenging efficiency and comprehensive antioxidant capacity in walnut seedlings through the synergistic regulation of key metabolic pathways, effectively mitigating salt stress. These findings establish a crucial mechanistic foundation for understanding plant salt stress responses and advance the utilization of MeJA-mediated strategies for the genetic improvement of salinity tolerance in walnut. Future research should prioritize optimizing MeJA application protocols and functionally validating key regulatory genes for breeding applications. Full article

The air quality in the Beijing–Tianjin–Hebei region of China has markedly improved in recent decades. Characterizing current PM_2.5 transmission between cities in light of the continuous reduction in emissions from various sources is of great significance for the formulation of future regional joint prevention and control strategies. To address these issues, a WRF-CAMx modeling project was implemented to explore the pollution characteristics from the perspectives of transport flux, regional source apportionment, and the comprehensive impact of multiple pollutants from 2013 to 2020. It was found that the net PM_2.5 transport flux among cities declined considerably during the study period and was positively affected by the continuous reduction in emission sources. The variations in local emissions and transport contributions in various cities from 2013 to 2020 revealed differences in emission control policies and efforts. It is worth noting that under polluted weather conditions, obvious interannual differences in PM_2.5 transport fluxes in the BTH region were observed, emphasizing the need for more scientifically based regional collaborative control strategies. The change in the predominant precursor from SO₂ to NOx has posed new challenges for emission reduction. NOx emission reductions will significantly decrease PM_2.5 concentrations, while SO₂ and NH₃ reductions show limited effects. The reduction in NOx emissions might have a fluctuating impact on the generation of SOAs, possibly due to changes in atmospheric oxidation. However, the deep treatment of NOx has a positive effect on the synergistic improvement of multiple air pollutants. This emphasizes the need to enhance the reduction in NOx emissions in the future. The results of this study can serve as a reference for the development of effective PM_2.5 precursor control strategies and regional differentiation optimization improvement policies in the BTH region. Full article

The article describes a basic comparison of soldering materials (preforms) from several suppliers, focusing on the main differences in surface structure, internal structure, and contamination on the surface and in the interior of the solder. As a result, we are able to define how different preforms of the surface, preforms related to impurities, or preforms of the structures of the composition parts of the power modules, which are subjected to the soldering process, influence the formation of different void types. Simultaneously an investigation of the impact on the soldering process (heating, cleaning, soldering, cooling), which influences the formation of the solder joint and on the formation intermetallic structure (IMC) and voids, is performed as well. A comparison of the individual results between RTG or X-ray (Radioisotope Thermoelectric Generator) and SAM (Scanning Acoustic Microscopy) are given together with the highlighted differences. This application study was carried out under various settings to investigate the effects of temperature and exposure time on formic acid. The findings confirm that oxide reduction is a time-dependent process. The lowest average void area—0.2%—was observed at the highest tested temperature of 230 °C, and the longest formic acid exposure duration of 300 s. Full article

Current intra-articular therapies with hyaluronic acid (HA) provide symptomatic relief in joint diseases, but have limited efficacy in counteracting oxidative stress and inflammation, key drivers of cartilage degradation in rheumatoid arthritis (RA). To address this limitation, the potential of combining HA with the phytochemicals xanthohumol (XAN) and epigallocatechin-3-O-gallate (EGCG), known for their antioxidant and anti-inflammatory properties, was evaluated in a cellular model of RA (SW982 synoviocytes stimulated with interleukin-1β, IL-1β). The Chou–Talalay method demonstrated that their combination synergistically reduced reactive oxygen species (ROS) and nitric oxide (NO) levels. The “TRIPLE” combination (HA + XAN + EGCG) showed the lowest combination index and the highest dose reduction index. Compared to individual treatments, TRIPLE significantly decreased IL-1β-induced IL-6, IL-8, TNF-α, and MMP-3 levels, while increasing the levels of the anti-inflammatory cytokine IL-10. Western blot analysis revealed a marked reduction in iNOS, COX-2, and MMP-3 protein expression following TRIPLE treatment. Moreover, the combination inhibited IL-1β-induced phosphorylation of IκB and p65, thereby preventing NF-κB activation. These findings suggest that integrating XAN and EGCG into injectable HA formulations may represent a promising strategy to improve the management of joint inflammation in RA. Full article

To address solder paste drawbacks, such as die contamination and flux residue, a polymer-based sheet containing Sn-3.0 (wt%) Ag-0.5Cu solder particles as fillers was fabricated, and its bonding characteristics were analyzed. The reductant in the manufactured sheet evaporated while removing the oxide layers on the solder and copper finish surfaces during heating. Subsequently, the resin component (polymethyl methacrylate) began to decompose thermally and gradually dissipated. Ultimately, the resulting joint formed a solder interconnection with a small amount of residual resin. This joint is expected to exhibit superior thermal conductivity compared with composite joints with a polymer matrix structure. Die-attach tests were conducted in air using the fabricated sheet between Cu finishes. Results showed that joints formed at 300 °C for 30 s and 350 °C for 10 s provided excellent shear strength values of 48.0 and 44.3 MPa, respectively, along with appropriately developed intermetallic compound (IMC) layers at the bonding interface. In contrast, bonding at 350 °C for 60 s resulted in excessive growth of IMC layers at the interface. When comparing size effects of solder particles, type 6 particles exhibited superior shear strength along with a relatively thinner total IMC layer thickness compared to when type 7 particles were used. Full article

Hyperuricemia, induced by monosodium urate (MSU) crystals that accumulate in articular joints and periarticular soft tissues, can impair macrophages. Possible causes of macrophage injury include uric acid-induced oxidative stress or inflammation. This study examined the dried fruits of guava (DFG) as a complementary medicine with urate-lowering properties, utilizing THP-1 macrophages to determine if high uric acid-induced cellular damage could be mitigated through the reduction of oxidative stress and inflammation via treatment with a phytochemical extract. The active extract was prescreened using a xanthine oxidase (XO) inhibition assay coupled with fractionation and component analysis. The DFG extracts were used to identify, through an in vitro study of THP-1 cells. The results indicated that the DFG extracts with the highest total flavonoids (12.08 ± 0.81 mg/g DW) exhibited the XO inhibition activity. High-performance liquid chromatography–tandem mass spectrometry analysis showed that DFG extract contained 85.32% flavonoids, including quercetin and kaempferol derivatives. Furthermore, fractionation results of DFG extracts indicated a significant reduction in MSU-induced cytotoxicity in THP-1 cells obtained from the 75% ethanol-eluted fraction (Fr-75). Additionally, kaempferol, an active compound in Fr-75, effectively mitigated MSU-induced NF-κB and NLRP3 gene overexpression. These findings suggest that the prepared Fr-75 is a promising hyperuricemia therapeutic candidate. Full article

Background: Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage breakdown, synovial inflammation, and pain, which leads to significant disability. IAHA is widely used because of its viscoelastic properties, which restore synovial fluid homeostasis and reduce symptoms. However, emerging evidence suggests that IAHA exerts additional biological effects including chondroprotection, inflammatory modulation, oxidative stress reduction, and pain modulation, which may influence disease progression. Objective: This narrative review examines the biological mechanisms underlying IAHA’s role in OA management. The review explored IAHA’s effects on synovial fluid viscoelasticity, inflammatory cytokine modulation, cartilage preservation, oxidative stress regulation, and pain pathways, emphasizing the influence of molecular weight variations on therapeutic efficacy. Additionally, this review evaluates IAHA’s integration into multimodal treatment strategies, its potential disease-modifying effects, and future directions for personalized treatment approaches. Methods: A comprehensive literature review was conducted using PubMed, Cochrane Library, EMBASE, Scopus, and Web of Science for studies published between January 2000 and March 2024. The search focused on IAHA’s molecular, cellular, and biochemical effects in OA and clinical findings assessing its impact on joint function, pain relief, and disease progression. Results: IAHA improves synovial fluid lubrication, reduces proinflammatory cytokines (IL-1β, TNF-α), inhibits matrix metalloproteinases (MMPs), scavenges reactive oxygen species (ROS), and modulates nociceptive pathways. High-molecular-weight IAHA demonstrates superior efficacy in advanced OA, while low-molecular-weight formulations may be better suited for early-stage disease. Although IAHA’s symptom relief is comparable to corticosteroids and NSAIDs, its favorable safety profile and emerging disease-modifying potential support its long-term use in OA management. Conclusions: IAHA represents a multifaceted therapeutic approach bridging symptomatic relief and regenerative strategies. While long-term efficacy, optimal administration protocols, and patient-specific responses remain subjects of ongoing research, refining treatment selection criteria, dosing regimens, and combination strategies may enhance clinical outcomes. Future studies should explore biomarker-driven approaches, standardize treatment protocols, and assess IAHA’s synergy with regenerative medicine to optimize its role in OA management. Full article

Despite the significant economic and environmental advantages of friction stir spot welding (FSSW) and its amazing results in welding similar and dissimilar metals and alloys, some of which were known as unweldable, it has some structural and characteristic defects such as keyhole formation, hook defects, and bond line oxidation. This has prompted researchers to focus on these defects and propose and investigate techniques to treat or compensate for their deteriorating effects on microstructural and mechanical properties under different loading conditions. In this experimental study, sheets of AA6061-T6 aluminum alloy with a thickness of 1.8 mm were employed to investigate the influence of reinforcement by graphene nanoplatelets (GNPs) with lateral sizes of 1–10 µm and thicknesses of 3–9 nm on the static and fatigue behavior of FSSW lap joints. The welding process was carried out with constant, predetermined welding parameters and a constant amount of nanofiller throughout the experiment. Cross-sections of as-welded specimens were tested by optical microscope (OM) and energy-dispersive spectroscopy (EDS) to ensure the incorporation of the nanographene into the matrix of the base alloy by measuring the weight percentage (wt.%) of carbon. Microhardness and tensile tests revealed a significant improvement in both tensile shear strength and micro-Vickers hardness due to the reinforcement process. The fatigue behavior of the GNP-reinforced FSSW specimens was evaluated under low and high cycle fatigue conditions. The reinforcement process had a detrimental effect on the fatigue life of the joints under cyclic loading conditions. The microstructural analysis and examinations conducted during this study revealed that this reduction in fatigue strength is attributed to the agglomeration of GNPs at the grain boundaries of the aluminum matrix, leading to porosity in the stir zone (SZ), the formation of continuous brittle phases, and a transition in the fracture mechanism from ductile to brittle. The experimental results, including fracture modes, are presented and thoroughly discussed. Full article

Background: With global warming and climate change, the occurrence of abiotic stresses has become increasingly prevalent. Drought often occurs with high temperatures, especially in arid and semi-arid regions. However, the molecular mechanisms of plants responding to combined drought and high-temperature stress remains unclear. Results: Through integrative physiological, transcriptomic, and metabolomic analyses, we systematically investigated the adaptive mechanisms of Dendrobium huoshanense under combined drought and high-temperature stress. Our findings revealed that combined drought and high-temperature stress led to significant reductions in photosynthetic efficiency and increased oxidative damage in Dendrobium huoshanense, with high-temperature stress being the primary contributor to these adverse effects. The joint analysis shows that three core pathways—signal transduction, lipid metabolism, and secondary metabolite biosynthesis—were identified as critical for antioxidant defense and stress adaptation. Conclusions: These findings not only deepen our understanding of plant responses to combined drought and high-temperature stress but also provide new directions for future research on the cultivation and resistance improvement of Dendrobium huoshanense. Full article

Previous studies have shown that a one-time application of polymer-coated urea (PCU) can increase rice yield and nitrogen (N) uptake. However, the connection between rice root morphology and physiological traits and grain yield and N absorption has still not been well understood. The objective of this study was to explore whether one-time application of PCU could enhance shoot growth, improve plant physiological activity, and ultimately boost rice yield and NUE by optimizing root morphological and physiological traits. In this study, a super-large-panicle indica-japonica hybrid rice variety, Yongyou1540, was cultivated under three N treatments during 2022 and 2023: (1) 0N, throughout the entire growth period, no N fertilizer was applied; (2) LFP, local farmers’ N management practices were followed, using urea as the N source, and N fertilizer management was carried out according to the local farmers’ customary fertilization practices; and (3) PCU, a one-time application of PCU was performed at one day before transplanting. PCU is a controlled-release fertilizer in which urea granules are coated with a synthetic polymer layer; it has been widely used in rice cultivation. In both LFP and PCU treatments, N was applied at a rate of 200 kg N ha⁻¹. PCU is a type of controlled-release fertilizer in which urea granules are coated with a layer of synthetic polymer. Compared to LFP, PCU significantly improved several root morphological traits, including increased deep-root proportion and specific root length (SRL), throughout the entire growth period; increased root length and root length density at heading and maturity; and increased root biomass growth rate from jointing to heading and reduced reduction rate after heading. Additionally, PCU enhanced root oxidative activity (ROA) and increased zeatin and zeatin riboside (Z+ZR) content in both roots and root bleeding sap at the middle and late grain-filling stages. Furthermore, PCU markedly increased the flag-leaf net photosynthetic rate, Z+ZR content in leaves, and activities of key enzymes involved in sucrose-to-starch conversion in grains during the middle and late grain-filling stages. Correlation analysis indicated that root and shoot biomass growth rate showed a significant positive correlation before heading, and that root biomass reduction rate was significantly negatively correlated with shoot biomass growth rate after heading. ROA and Z+ZR content in both roots and root bleeding sap were significantly associated with flag-leaf photosynthetic rate, Z+ZR content in leaves, and the activities of key enzymes involved in the sucrose-to-starch conversion in grains. On average, PCU increased rice yield by 10.0% and agronomic NUE by 46.2%, compared to LFP. These findings suggest that PCU could optimize root morphological and physiological traits, and thereby promote shoot growth, enhance physiological activity, and ultimately increase both rice yield and NUE. Further research could also investigate the potential for combining PCU with other agronomic practices to enhance both rice yield and NUE. Full article

Background: Knee osteoarthritis (OA) is a common and debilitating disorder marked by joint degradation, inflammation, and persistent pain. This study examined the possible therapeutic effects of curcumin and vitamin D on OA progression and pain in a rat knee OA model by anterior cruciate ligament transection and meniscectomy (ACLT + MMx). Methods: Male Wistar rats were categorized into five groups: control, curcumin-treated (100 mg/kg/day), vitamin D-treated (25 µg/kg/day), a combination of vitamin D and curcumin, and sham-operated. All supplements were administered orally on a daily basis for 12 weeks. Pain behaviors were assessed, serum biomarkers were measured, and knee histology was examined. Results: Both curcumin and vitamin D independently reduced pain, while the combined group exhibited better analgesic effects. Serum inflammatory cytokines demonstrated a decrease in pro-inflammatory cytokines and an elevation in anti-inflammatory cytokine interleukin-10 (IL-10) in the supplement groups. The antioxidative markers were partially recovered by curcumin and vitamin D supplement. However, the oxidative stress marker Cartilage Oligomeric Matrix Protein (COMP) was significantly reduced. Histology analysis revealed a preservation of joint architecture and cartilage integrity and decreased synovium inflammation in the groups treated with curcumin and vitamin D. Conclusions: Our findings indicate a dual mechanism that encompasses the role of anti-inflammation and antioxidation on knee OA progression and pain reduction, underscoring the potential of these natural chemicals as therapeutic agents for knee OA; curcumin and vitamin D supplement may be added in delaying knee OA progression and associated pain management in clinical patient care. Full article