Search Results (1,935)

Polycrystalline diamond (PCD) has broad application prospects in semiconductors, optical windows and other advanced fields. Nevertheless, its ultrahigh hardness and chemical inertness pose significant challenges for achieving high-quality surface planarization. Although conventional mechanical lapping is widely adopted, it still suffers from poor surface quality and a lack of theoretical guidance for process parameter selection. This study presents a systematic experimental and simulation investigation on both rough and fine lapping of PCD, focusing on tool selection and process optimization. In the rough lapping stage, three types of fixed diamond abrasive discs with resin, bronze, and vitrified bonds were compared. The soft and tough resin-bonded disc yields the best performance, reducing surface roughness Ra from 420 nm to 106 nm. In the fine lapping stage, three metallic discs—Cu, Fe, and WC-Co—were evaluated. The high-stiffness WC-Co disc achieves the best results, with an Ra of 11.2 nm under conditions of 0.45 MPa and 600 r/min. Molecular dynamics (MD) simulations further reveal that increasing lapping pressure significantly enhances the material removal rate but concurrently aggravates subsurface damage (SSD), while the effect of speed is considerably smaller. Therefore, pressure emerges as the key parameter that requires balanced optimization in the fine lapping process. Full article

The mixed application of plant residues to treat petroleum-contaminated soil may increase remediation efficiency by leveraging their mixed decomposition effects. However, it remains unclear whether this approach may also lead to opposite effects. In this study, plant residues of 7 common plant species, namely, Bothriochloa ischaemum (Bi), Lespedeza davurica (Ld), Artemisia gmelinii (Ag), Heteropappus altaicus (Ha), Artemisia annua (Aa), Sophora davidii (Sd), and Agropyron cristatum (Ac), from the petroleum-producing area of northern Shaanxi and their 9 mixtures were used to treat petroleum-contaminated soil with a crude oil content of 15.00 g kg⁻¹. The samples were incubated at 25 °C under constant humidity for 120 days to determine the potential effects of mixed plant residues on stimulating contaminant degradation and restoring soil biological and chemical properties. The results revealed that (1) among all mixed plant residue treatments, combinations of BiLdAg, LdSd and HaAa significantly weakened the overall contaminant degradation efficiency. In particular, the LdSd and HaAa mixtures simultaneously strongly inhibited the degradation of saturated hydrocarbons and aromatic hydrocarbons; compared with the expected theoretical values, their degradation rates decreased by 12.36–35.25% and 9.91–19.82%, respectively (p < 0.05). (2) Mixtures including LdAgHa, BiLdAg, LdSd, LdAgHaAa, LdHa and HaAgAcSd significantly impaired the capacity of plant residues to replenish soil available nutrients and activate soil enzyme activities. The LdAgHa mixture exhibited the strongest antagonistic effect: its improvement efficiency in terms of soil nitrate nitrogen content and sucrase, dehydrogenase and polyphenol oxidase activities (the increase relative to that in contaminated soil) decreased by 30.60–76.89% relative to the theoretical expectations (p < 0.05). Overall, the effects of mixed plant residue addition on contaminant degradation and the restoration of damaged soil biochemical properties were negatively correlated. (3) Increased chemical specialization of mixed residues and higher mass proportions of Ld and Bi residues in mixtures tended to aggravate the above antagonistic inhibitory effects. When all the remediation indicators were comprehensively evaluated, the mixed application of plant residues failed to universally improve the remediation performance of crude oil-contaminated soil. Under experimental conditions, BiLdAg and LdSd residue combinations may lead to remarkable antagonistic interactions and lower the efficiency of necrophytoremediation, which should be avoided in practical field applications of this remediation technology. Full article

Lead (Pb) pollution is a global public health issue, yet the mechanisms underlying Pb-induced kidney aging remain poorly understood. Selenium (Se), an essential trace element critical for kidney health, primarily exerts its physiological roles via selenoproteins; among them, membrane-bound selenoproteins strategically localized at the endoplasmic reticulum and plasma membrane, have emerged as potential molecular links in Se-mediated protection. In this study, Hyline chicken models (treated with 350.00 mg/L Pb or/and 1.00 mg/kg Se) and HK-2 cell models (treated with 200 μM Pb or/and 2.5 μM Se) were established to investigate the protective mechanism of Se to Pb poisoning in kidneys, with emphasis on membrane-bound selenoproteins and kidney aging. Results showed that Pb significantly decreased (p < 0.05) membrane-bound selenoproteins and induced kidney aging. Inflammation and autophagy were involved, as Pb significantly increased (p < 0.05) pro-inflammatory cytokines interleukin-4 (IL-4) and interleukin-12β (IL-12β), and autophagy-related genes autophagy related 5 (ATG5), BCL2 interacting coiled coil protein 1 (Beclin 1), and microtubule-associated protein 1A/1B-light chain 3 (LC3-II) while significantly suppressing (p < 0.05) interleukin-2 (IL-2) and mammalian target of rapamycin (mTOR). Se had a relieving effect on it, as evidenced by significantly reversing (p < 0.05) the changes in the above indicators. Interestingly, Selenoprotein T (SELENOT), as a hub membrane-bound selenoprotein, is sensitive to Pb poisoning (Pb exposure decreased SELENOT mRNA expression to 56%, 34%, and 19% of the control levels at 30, 60, and 90 days, respectively). Knockdown of SELENOT aggravated Pb-induced inflammation, autophagy, and cellular senescence, meaning that SELENOT protected against kidney aging via suppressing inflammation and autophagy under Pb stress. These findings establish membrane-bound selenoproteins as essential molecular hubs that orchestrate inflammation resolution and autophagy in Se’s antagonism against Pb-induced kidney aging, highlighting promising therapeutic targets for nephropathy. Full article

Delayed floor water inrush can be triggered during deep coal seam mining in Northern China under the coupled effects of Ordovician limestone confined aquifers and fault structures. Taking a typical working face threatened by a confined aquifer as the engineering background, this study investigates the hydraulic erosion-induced instability of fault fracture zone fillings and the formation mechanism of water-conducting pathways by integrating compositional analysis of fault-zone fillings, laboratory seepage tests, and numerical simulations. The results show that the fault fillings are dominated by fine-grained clay minerals, mainly including kaolinite, illite, illite–smectite mixed-layer minerals, and montmorillonite. Under mining-induced disturbance and confined water pressure, these fillings are prone to pore-structure reconstruction and permeability enhancement. The seepage process in the fractured rock mass exhibits pronounced non-linearity and can be divided into three stages: initial seepage, abrupt seepage transition, and stable seepage. The migration and loss of fine particles are the key factors controlling the formation of water-conducting pathways and the increased risk of water inrush. As the fracture-zone width increases, fault dip angle and aquifer water pressure all enhance fault water-conducting capacity, promote the upward migration of confined water along the fracture zone, and aggravate the risk of floor water inrush at the working face. The research achievement can provide an important reference for elucidating and controlling floor water-inrush mechanisms in confined-aquifer working faces affected by faults in similar engineering conditions. Full article

2-phenylbenzimidazole-5-sulfonic acid (PBSA) is a commonly used organic ultraviolet (UV) filter frequently found in aquatic environments, raising substantial ecological health concerns. While some toxic effects of PBSA on aquatic organisms have been reported, its intergenerational developmental and neurotoxic risks remain poorly understood. In this study, we established a zebrafish life-cycle exposure model to explore the intergenerational toxicity of environmentally relevant concentrations of PBSA (0.2, 2, and 20 μg/L). Offspring were categorized into three exposure groups: parental exposure only (F0+/F1−), parental exposure with continuous F1 exposure (F0+/F1+), and only F1 exposure without parental treatment (F0−/F1+). Our findings demonstrate the transfer of PBSA from parental gonads to F1 embryos. Parental lifetime exposure significantly inhibited somitogenesis and increased mortality and malformation rates in the F1 generation, with the most pronounced developmental damage observed in the F0+/F1+ group. Whole-mount immunohistochemistry revealed that PBSA notably reduced motor neuron axon length in F1 larvae, accompanied by downregulation of developmental-related genes including gap43, mbp, and shha. Mechanistically, the F0+/F1− group exhibited a marked increase in MDA levels. Excessive ROS accumulation and reduced CAT activity were specifically observed in the F0+/F1+ group, whereas the F0+/F1− and F0−/F1+ groups showed significantly elevated CAT activity, jointly driving developmental and neurotoxic changes. In silico predictions indicated low acute aquatic toxicity of PBSA, contradicting its observed intergenerational risks. Our findings demonstrate that parental lifetime PBSA exposure can induce significant intergenerational neurodevelopmental toxicity in zebrafish offspring by disrupting oxidative balance and neural gene expression, with continuous offspring exposure further aggravating the adverse effects. This research underscores that traditional single-generation toxicity assessments underestimate the ecological dangers of UV filters. It also offers new insights into the environmental risk evaluation of PBSA and similar emerging contaminants. Full article

This study proposes an intelligent speed-loop controller for a brushless DC motor (BLDCM) drive implemented under a field-oriented control (FOC) scheme. The controller is constructed by embedding the coati optimization algorithm (COA) into a composite sliding mode theory (CSMT) control structure. In sliding mode control (SMC), the use of only one reaching law normally produces a design trade off: increasing the reaching speed tends to aggravate overshoot or chattering, whereas reducing switching activity often slows convergence. To mitigate this compromise, the proposed controller adopts a composite reaching law (CRL) formed by an exponential component and a power component. When the system trajectory is distant from the sliding surface, the exponential component strengthens the reaching action and shortens the transient interval. When the trajectory moves close to the sliding surface, the power component decreases the effective switching intensity, thereby attenuating high-frequency chattering and reducing the overshoot associated with an aggressive exponential action. For adaptive gain selection, the COA search variables are chosen as four controller parameters: the sliding mode gain, the exponential reaching gain, the power reaching gain, and the power exponent. The fitness index is established from the rotor-speed tracking error and the time variation in that error. By imitating the hunting and predator-avoidance behaviors of coatis, the optimization process updates candidate solutions and selects the parameter combination that best matches the current operating condition. The resulting gains are supplied to the composite sliding mode controller (CSMC) so that the BLDCM can follow speed commands rapidly while preserving stable regulation. Because the proposed method performs online optimization of controller gains rather than data-driven training, it can be realized without a large training dataset. MATLAB/Simulink simulations are carried out to examine the effectiveness of the proposed strategy. The controller is compared with four benchmark methods, namely power reaching law (PRL)-based SMC, exponential reaching law (ERL)-based SMC, non-optimized composite reaching law SMC, and zebra optimization algorithm (ZOA)-assisted ERL-based SMC. The simulation results demonstrate that the proposed COA-based composite sliding mode controller improves both speed command-tracking and load-disturbance rejection relative to the comparative controllers. Full article

As an emergent contaminant, 6-PPD quinone (6-PPDQ) causes toxic effects in organisms, including induction of immunosuppression. Thiamine pyrophosphate (TPP) serves as an important cofactor for some metabolisms. We aimed to examine the role of thiamine pyrophosphokinase TPK-1 in modulating 6-PPD-induced immunosuppression. Using Caenorhabditis elegans as the animal model, 6-PPDQ-exposure treatment was applied to nematodes from the L1 larval stage to adult day 3, and innate immune response was assessed by the expression of antimicrobial genes. In nematodes, 6-PPDQ (1–10 μg/L) elevated TPP content, which was due to an increase in the expression of tpk-1, and RNAi of tpk-1 could block 6-PPDQ-induced immunosuppression. Meanwhile, RNAi of tpk-1 strengthened expressions of mitochondrial UPR (mt UPR) marker genes (hsp-6 and hsp-60) by activating three transcription factor (TF) genes (atfs-1, ubl-5, and dve-1) in 6-PPDQ-exposed nematodes. RNAi of mitochondrial UPR marker genes and three TF genes aggravated 6-PPDQ-induced immunosuppression. TPK-1 acted upstream of these three TF genes to modulate 6-PPDQ-induced immunosuppression. Moreover, RNAi of tpk-1 inhibited the expression of complex III/IV subunit genes, and RNAi of these complex III/IV subunit genes conferred resistance to 6-PPDQ-induced immunosuppression. Additionally, these complex III/IV subunit genes functioned upstream of TF genes (atfs-1, ubl-5, and dve-1) to regulate 6-PPDQ-induced immunosuppression. Therefore, our data provide a novel basis for 6-PPDQ-induced immunosuppression mediated by activation of TPK-1 and the following mt UPR suppression. Full article

Coal-mining-induced goaf areas are widely distributed in China and pose potential risks to high-speed railways. Repeated train-induced cyclic loading may further disturb the already weakened ground and aggravate deformation of the subgrade. A study on the goaf ground soil along the Taijiao High-Speed Railway utilized a GDS dynamic triaxial apparatus and controlled variable method to examine how waveforms, cyclic stress ratios (CSRs), effective confining pressures, vibration frequencies and cycles affect soil dynamics. The results show that cumulative plastic strain and residual pore pressure ratio generally tended to stabilize after rapid early development; however, both responses increased markedly within the 2–3 Hz frequency range. Among the investigated variables, the cyclic stress ratio (CSR) exerted the most significant influence and showed an exponential relationship with cumulative plastic strain and residual pore pressure ratio, whereas effective confining pressure produced a nearly linear decreasing trend. A dynamic stress–strain backbone curve was constructed, and by introducing the influence of vibration cycles into the H-D framework, the modified model achieved better agreement with the experimental backbone curves than the conventional H-D model. Furthermore, ABAQUS simulations further demonstrated that train speed and subgrade form significantly influence the distribution of dynamic stress and vertical displacement in goaf ground, with a more severe response in the cutting section. The optimized constitutive model and numerical results provide theoretical support for foundation design, long-term stability assessment and settlement prediction of high-speed railways constructed over goaf ground. Full article

Inflammation is a physiological response of the body to infection and tissue damage; dysregulated inflammatory signaling can cause the initiation and aggravation of a variety of chronic diseases. Although anti-inflammatory drugs have been commercialized and showed beneficial effects clinically, their long-term application is often limited by loss of effects and adverse side effects. Natural polysaccharides are multifunctional biomacromolecules with strong potentials in inflammation therapy due to their inherent biocompatibility, wide immunomodulation property and drug capacity. In this Review, we offer a holistic summary of recent advances in polysaccharide anti-inflammatory strategies by coupling the characteristics of structure, biological mechanism and polysaccharide-based delivery systems. This review gives a comprehensive overview of the rational design of anti-inflammatory strategies based on polysaccharides, and also points out the current limitations of polysaccharide drugs in applications, translation difficulties and future trends. Full article

Seabed scour-induced degradation of the pile–soil system, together with the coupled action of seismic, wind and wave loads, poses great challenges to the long-term service safety of jacket-type offshore wind turbines. In this study, an integrated structural numerical model is established with consideration of nonlinear pile–soil interaction. By coupling OpenFAST (Version 3.5.0) and OpenSees (Version 3.7.0), accurate wind and wave load generation and refined calculation of structural dynamic responses are achieved. Then, the dynamic performance of jacket-type offshore wind turbines under combined wind–wave–seismic loads is analyzed at different scour depths (0D, 1D, 2D and 3D, where D is the pile diameter). Structural response characteristics before and after seismic excitation are emphatically compared under two typical sea states: collinear wind–wave condition (COD-2.2) and non-collinear wind–wave condition (MIS-2.4). The results show that seismic excitation substantially amplifies structural dynamic responses. Meanwhile, strong seismic interference weakens the influence of wind–wave directionality to a certain degree, lowering the response difference between the COD-2.2 and MIS-2.4 cases. It is further found that scour depth remains the dominant factor controlling pile internal forces and foundation lateral deformation even when seismic effects are incorporated. Moreover, under the selected Chi-Chi ground motion, scour aggravation markedly increases the seismic response amplification and internal force concentration of the structure. This research provides a theoretical reference for the multi-hazard resilience design and assessment of wind turbine foundations under complex marine environments. Full article

Permanent magnet synchronous motors (PMSMs) are widely employed in electric vehicles owing to their high efficiency, high power density, and wide speed regulation capability. However, electromagnetic vibration is aggravated by the non-sinusoidal air gap magnetic field distribution and cogging torque. To suppress vibration, this paper proposes an optimized asymmetric rotor design. Through sensitivity analysis of rotor parameters on motor performance, a high-precision Metamodel of Optimal Prognosis (MOP) is developed for the surrogate-based motor model. Subsequently, rotor parameters are comprehensively optimized using a genetic algorithm. The results demonstrate that, compared with the reference motor under identical operating conditions, the optimized motor maintains equivalent output torque while achieving significant reductions in vibration-related performance indicators: torque ripple is reduced by 17.9%, and cogging torque is reduced by 82.8%, the amplitude of the 48th-order electromagnetic force decreases from 2.60 N to 1.28 N (representing a 50.7% reduction), and the peak vibration response decreases from 109.7 dB to 107.2 dB. This study provides an effective design approach for electromagnetic vibration suppression in PMSMs. Full article

The disengagement of contact wires in rigid overhead contact systems (ROCS) is a critical hazard to urban rail transit, potentially causing pantograph–catenary collisions, wire breakage, and large-scale catenary failures. To investigate its mechanical mechanism and detection approach, a three-dimensional solid and flexible multibody coupled model of a rigid pantograph–catenary system was established using finite element analysis and multibody dynamics simulation. The effects of train speed, contact force fluctuation, contact wire stress concentration, and disengagement degree on pantograph–catenary dynamic behavior were analyzed. The results show that the standard deviation of contact force at overlapping spans is significantly higher than that in other sections, indicating that overlapping spans are high-risk regions for disengagement. The peak stress of the contact wire is mainly concentrated at registration points and increases with train speed, which may promote abnormal wear and local deformation of the conductor rail jaw. Field-observed environmental degradation factors, such as tunnel water leakage, corrosion, and conductive grease deterioration, may further weaken the clamping performance of the conductor rail. Hazard simulations show that disengagement at overlapping spans deteriorates current collection quality and aggravates carbon strip wear, especially at the beginning of the subsequent overlapping span. Based on onboard inspection equipment, an engineering detection route integrating area-scan imaging, three-dimensional profile scanning, and line-scan imaging is proposed to support the inspection of severe and minor disengagement defects. Full article

Background: Rheumatoid arthritis (RA) is influenced by environmental exposures. High humidity has been clinically associated with worsened joint symptoms, but the microbial and metabolic mechanisms remain unclear. We investigated whether a gut microbiota–metabolism axis contributes to humidity-associated aggravation of collagen-induced arthritis (CIA). Methods: CIA mice were maintained under normal or high relative humidity. We integrated 16S rRNA and metagenomic sequencing, liquid chromatography–tandem mass spectrometry metabolomics, and intestinal barrier assessments. Fecal microbiota transplantation (FMT) was performed to evaluate microbiota dependency. Based on multi-omics findings, we quantified chondroitin sulfate (CS) and conducted functional experiments involving Prevotella stercorea (P. stercorea) supplementation, CS administration, and in vitro degradation assays. Results: High humidity aggravated arthritis severity and systemic inflammation, including increased interleukin-6, interleukin-17A, and granulocyte colony-stimulating factor, and was accompanied by impaired intestinal barrier integrity. FMT supported a microbiota-dependent contribution. Metagenomic analysis identified enrichment of P. stercorea and glycosaminoglycan degradation pathways under high humidity. CS abundance was reduced in articular cartilage, P. stercorea degraded CS in vitro and was associated with cartilage CS loss in vivo, and CS supplementation attenuated arthritis under high humidity and reduced the arthritis-promoting effects associated with P. stercorea. Conclusions: High humidity is associated with microbiota-dependent functional remodeling, enhanced CS degradation, and aggravated arthritis in CIA mice. These findings suggest that humidity-associated alterations in microbial CS metabolism may link environmental exposure to cartilage disruption and joint inflammation. Full article

2.5D C/SiC composites are characterized by high hardness and brittleness. These properties render the composites prone to fiber fracture, burr formation and matrix damage during grinding for hole-making. This study systematically investigates the material removal mechanism, tool wear behavior and machining quality evolution process during diamond core drill grinding for hole-making. Through experiments, the effects of grinding angle and grinding force and the thermal effects on material removal characteristics and hole wall machining quality were analyzed, and the stagewise characteristics of tool wear and the correlation between processing parameters and machining quality were clarified. The results indicate that the wear of diamond core drills undergoes a three-stage evolution: slight abrasive grain shedding at the initial stage, local damage and wear loss at the middle stage, and large-scale abrasive grain peeling followed by tool failure at the late stage. As wear aggravates, the machining axial force increases remarkably and the grinding temperature rises drastically. Hole wall defects gradually develop from minor initial fiber fracture into complex failure modes including burrs, fiber pull-out and matrix damage. In particular, the morphological degradation at the hole exit is the most severe. This study verifies that the optimization of process parameters and tool design can improve machining quality, and provides theoretical guidance and an experimental basis for the efficient and precise machining of high-performance composites. Full article

Background/Objectives: This study is the first to investigate the potential mechanism of star anise extract (SAE) in protecting against cold stress-aggravated acute lung injury (CSALI) in rats. Methods: A rat CSALI model was induced via combined lipopolysaccharide challenge and cold stress exposure. The preventive effects of SAE were evaluated using cytotoxicity assays, quantification of biochemical indices and inflammatory factors, and histopathological examination. Ultra-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC–HRMS)-based serum metabolomics was employed to systematically profile CSALI-associated metabolic alterations and decipher the potential mechanism underlying the preventive effects of SAE. Results: SAE alleviated pathological progression of CSALI, suppressed inflammatory cell migration, markedly reduced pulmonary inflammatory cell infiltration, and ameliorated lung tissue injury in CSALI rats. SAE also improved abnormal liver function indicators and lowered the levels of pro-inflammatory factors in both serum and bronchoalveolar lavage fluid (BALF). Serum metabolomics analysis identified and annotated 24 disease-altered differential metabolites and evaluated the protective effects of SAE on them. These metabolites were significantly enriched in two key metabolic pathways related to the pathogenesis of CSALI, including arachidonic acid metabolism and glycerophospholipid metabolism. Furthermore, based on metabolite changes, phospholipase A2 was hypothesized as a potential key regulatory factor that may cooperate with arachidonic metabolism to suppress the inflammatory cascade. Conclusions: These findings demonstrated that SAE exerted prominent anti-inflammatory activity and effectively protected against lung injury in CSALI rats. Full article