Search Results (1,163)

The coordination polymerization of 1,3-butadiene with half-metallocenes/MAO catalysts is a versatile route to polybutadiene, yet the kinetic impact of catalyst preparation remains poorly understood. This work compares CpTiCl₃/MAO systems prepared either in situ or by aging as a function of [MAO]/[Ti], temperature, and the presence of residual trimethylaluminum (TMA) in MAO. Aged catalysts display markedly higher activity than in-situ systems, achieving up to 99% conversion at [MAO]/[Ti] = 250 (vs. 34% in situ) while maintaining similar molecular weights and cis-1,4 microstructure (76–77%). Because the in-situ and aged systems were evaluated at different titanium concentrations, this activity difference should be interpreted as arising from both catalyst pre-conditioning and differences in effective Ti concentration. Time-resolved GPC coupled with chromatogram deconvolution reveals two coexisting macromolecular populations, associated with kinetically distinct chain-growth contributions. For aged systems, the corresponding apparent propagation rate constants remain of the same order of magnitude throughout the reaction, consistent with persistent catalytic heterogeneity rather than progressive site deactivation. The role of residual trimethylaluminum (TMA) in commercial MAO is clarified: TMA accelerates initial activation and enhances chain transfer processes, lowering molecular weight and broadening dispersity, but does not measurably affect cis-1,4 selectivity, which is governed by the ligand environment of CpTiCl₃. Overall, thermal aging and MAO conditioning emerge as effective tools to tune the kinetic behavior of CpTiCl₃/MAO catalysts without compromising microstructural control in polybutadiene synthesis. Full article

This study highlights the strong ability of a new bacterial strain, Hafnia paralvei UUNT_MP29, isolated from the gastrointestinal tract (GIT) of common carp (Cyprinus carpio), to break down polystyrene (PS). As an omnivorous bottom feeder, C. carpio is constantly exposed to microplastics, creating a unique environment that favors the evolution of specialized microbiota capable of degrading polymers. Genomic analysis of the isolate identified key homologs involved in xenobiotic breakdown, including alcohol dehydrogenase (Adh), 3-hydroxybutyrate dehydrogenase (HDH), and a small glutamine-rich tetratricopeptide repeat-containing protein (SGTA), showing a strong metabolic system for processing long-chain hydrocarbons. Growth experiments showed the strain quickly adapted, reaching maximum cell density and forming mature biofilms by Day 16. Gravimetric analysis confirmed that H. paralvei UUNT_MP29 uses PS as its primary carbon source, with a significant weight loss of 16.76% over 16 days. Kinetic modeling indicated the degradation follows first-order kinetics (R² = 0.9243) with a high degradation rate constant (k) of 0.2078 day⁻¹. Surface analyses using FTIR and SEM confirmed extensive oxidative changes, as evidenced by the rising Carbonyl Index and surface erosion. TGA also showed reduced thermal stability of the treated polymer, suggesting microbial chain scission. These findings demonstrate the strong degradative ability of H. paralvei UUNT_MP29 and highlight the GIT of plastic-exposed aquatic animals as a promising area for discovering powerful biocatalysts for microplastic cleanup. Full article

In tennis, where performance is governed by complex kinetic chain interactions, objective skill classification is vital for coaching and talent identification. This study presents a hierarchical deep learning framework leveraging synchronized bilateral Inertial Measurement Unit (IMU) data from 39 participants (11 elite, 28 amateur). The proposed system successfully distinguishes expertise levels across a total of 4594 strokes, including augmented samples.. A hybrid Convolutional Neural Network-Bidirectional Long Short-Term Memory (CNN-BiLSTM) architecture was developed to autonomously extract spatiotemporal features from the raw kinematic signals of forehand, backhand, service, and volley strokes. The proposed model achieved an accuracy of 95.54%, significantly outperforming both traditional machine learning and state-of-the-art deep learning benchmarks. Qualitative t-distributed Stochastic Neighbor Embedding (t-SNE) analyses revealed that elite athletes form highly homogeneous clusters in the feature space. Furthermore, quantitative Asymmetry Index assessments confirmed that professionals exhibit superior bilateral coordination stability. These findings demonstrate that the proposed end-to-end system offers a robust, field-applicable solution for identifying technical excellence. It provides coaches with reliable digital biomarkers, thereby overcoming the limitations of subjective visual observation. Full article

Background: The overuse of traditional antimicrobial agents has accelerated the global spread of drug-resistant bacteria, posing a severe threat to global public health. Methods: In this work, a series of lipopeptides with varying fatty acid chain lengths were designed using the targeting antimicrobial peptide CL5 as the parental peptide. A variety of technical methods, including spectroscopic techniques, electron microscopy and computer simulation, were adopted to explore the self-assembly properties of the lipopeptides and their antimicrobial properties against Gram-positive and Gram-negative bacteria. Results: The results showed that lipopeptide self-assembly could be triggered by fatty acid chain modification with a carbon chain length exceeding 8 atoms, and hydrophobic interactions between fatty acid chains were the primary driving force for this process. The geometric mean of the minimum inhibitory concentrations of the lipopeptides exhibited an approximate “U”-shaped correlation with the length of the fatty acid chains. Among these lipopeptides, C8CL5–C12CL5 exhibited broad-spectrum and highly potent antimicrobial activity, with geometric means of 6.20, 5.16, and 8.00 μM against all tested bacteria, and selectivity index values of 12.26, 8.14, and 7.48, respectively. Furthermore, the lipopeptides exhibited high selectivity, rapid time-killing kinetics, as well as excellent thermal, pH and salt stability. Mechanistic studies revealed that the lipopeptides exerted antimicrobial effects through multiple pathways: disrupted bacterial cell membranes and caused the leakage of cellular contents, bound to bacterial genomic DNA, and promoted the production of reactive oxygen species. Conclusions: Collectively, lipopeptides modified with appropriate fatty acid chains exhibit broad-spectrum and highly effective antimicrobial activity, making them promising alternatives to traditional antibiotics for the treatment of bacterial infections. Full article

With the growing severity of water pollution, conventional treatment technologies are increasingly unable to satisfy the demand for deep purification. Catalytic wastewater treatment has emerged as an effective strategy for degrading refractory pollutants because of its high efficiency, mild operating conditions, and environmentally friendly nature. This review systematically summarizes recent progress in catalytic materials for wastewater treatment, covering four major categories: metal-based materials, carbon-based materials, multicomponent composites, and photo/electrocatalytic systems. Particular attention is given to their design strategies, structural characteristics, and performance advantages. On this basis, the full mechanistic chain is discussed, from interfacial adsorption and activation to reactive-species generation, including both radical and non-radical pathways, intermediate transformation, and macroscopic reaction kinetics. The review also highlights representative applications in practical wastewater streams, including textile dyeing and pharmaceutical, chemical, landfill leachate, and municipal tailwater treatment, thereby demonstrating the engineering potential of catalytic technologies. At the same time, several critical challenges remain, including insufficient long-term material stability, incomplete mechanistic understanding in complex water matrices, limited adaptability to real wastewater, and the high cost of large-scale preparation. Future research should therefore focus on the development of highly stable, low-cost, and interference-resistant catalytic materials, deeper mechanistic elucidation through in situ characterization and theoretical calculations, stronger integration with membrane separation, biological treatment, photovoltaic or electrochemical processes, and the establishment of standardized evaluation protocols and life-cycle assessment frameworks. These efforts will accelerate the transition of catalytic wastewater treatment toward greener, smarter, and more practical engineering applications. Full article

Background/Objectives: α-Mangostin, a natural product from Garcinia mangostana L, presents very strong antibacterial activity in plant flavonoids against Staphylococcus aureus. Recently, it was reported that the quinone pool is a key target of α-mangostin against Gram-positive bacteria. Here, the detail centering this action mechanism of α-mangostin killing S. aureus was further explored. Methods: The interactions between α-mangostin and type II NADH:quinone oxidoreductase (NDH-2), a key enzyme in the respiratory chain, were explored through the enzyme kinetic experiments, fluorescence analyses, and molecular simulation. Simultaneously, the effect of α-mangostin on membrane potential was also investigated as a possible non-enzymatic mechanism. Results: it was found that α-mangostin mainly competes the menaquinone-binding sites of NDH-2 with menaquinone, and the half-maximal inhibitory concentration (IC₅₀) of α-mangostin on NDH-2 is 4.95 μM. Fluorescence analyses indicated that α-mangostin can spontaneously bind to NDH-2 to form an α-mangostin–NDH-2 complex. Subsequently, molecular simulation further showed that α-mangostin can dock to the menaquinone-binding sites of NDH-2. In addition, non-enzymatic mechanism showed that α-mangostin can cause membrane potential depolarization and disrupt the proton motive force balance, thereby promoting the cell-membrane destruction of S. aureus. Conclusions: α-Mangostin can mainly interact with the amino acid residues at the menaquinone-binding pocket of NDH-2 to block the electron transfer at the quinone pool in the respiratory chain of S. aureus, which will hinder the energy supply and act synergistically with cell membrane damage, ultimately leading to the death of S. aureus. Simultaneously, it once again proves that the quinone pool is a key target of plant flavonoids against Gram-positive bacteria. Full article

Coal gasification fine ash (CGFA) is a carbon–mineral composite solid waste whose valorization is severely hindered by poor interfacial compatibility with organic media due to its highly polar surface. Here, we report a surface alkylation strategy using haloalkanes with variable chain lengths to systematically tune the surface chemistry and thermo-oxidative behavior of CGFA. Comprehensive spectroscopic characterizations (XPS, FTIR, and ¹³C NMR) confirm successful grafting of alkyl chains, which increases aliphatic C-H content from 24.8% to 43.9% while reducing polar carboxyl groups from 7.9% to 1.6%, with the mineral framework remaining intact. Thermogravimetric analysis reveals that alkylation lowers the onset decomposition temperature from 358 °C to 295 °C and enhances the maximum mass-loss rate. Kinetic analysis shows that grafted alkyl chains act as low-energy initiation sites, reducing the initial activation energy to 95 kJ/mol, while the later-stage oxidation becomes diffusion-limited. Notably, long straight-chain alkylation achieves the best performance, whereas branched chains are less effective due to steric hindrance and pore blockage. This work establishes a clear chain-length-dependent structure–thermal response relationship, positioning alkylated CGFA as a designable precursor for functional carbon materials, intelligent char-forming agents, and tunable components for energy or responsive material systems. Full article

The decoupling of physical loading configurations from dynamic temperature control in cold-chain logistics exposes supply chains to severe thermal compliance risks and exponential cost penalties. To address this structural gap, this study formulated the Cold Chain Unitization Loading Optimization Problem (CCULP). We propose a mixed-integer linear programming (MILP) model that integrates continuous-time heat-transfer dynamics—including door-opening impulse disturbances—and Q10-driven quality-decay kinetics as endogenous constraints within the hierarchical assignment of perishable goods to insulated containers, pallets, and vehicles. By treating container thermal resistance as a core decision variable, the model operationalizes a “prevention-first” economic strategy. To solve this NP-hard problem, we developed a Temperature-Aware Heuristic Algorithm (TAHA) that embeds a forward-Euler temperature simulation loop directly into the combinatorial search. Computational experiments on instances up to 100 SKU types demonstrate that TAHA achieves near-optimal solutions (within 0.7% of the MILP proven optimum) while converging 63 times faster than a genetic algorithm benchmark. Moreover, compared with traditional geometry-centric heuristics, TAHA’s proactive container-polarization strategy effectively eliminates the “penalty cliff,” yielding up to a 25.9% reduction in total system cost on Large-scale instances, almost entirely attributable to the elimination of temperature-violation penalties. Sensitivity analyses further confirm TAHA’s robustness under extreme environmental stress (e.g., 40 °C ambient temperatures) and frequent logistical disturbances, offering an integrated framework for proactive risk mitigation and for reducing food loss in sustainable temperature-controlled distribution. Full article

Overhead sports place high demands on the shoulder complex, making warm-up specificity relevant for acute readiness. This randomized controlled pilot trial compared the immediate effects of a shoulder-specific warm-up with a habitual routine in 24 youth competitive overhead athletes (14–20 years), allocated to an experimental group (EG = 12) and a habitual warm-up group (SWG = 12). The warm-up protocol was administered bilaterally to both shoulders, whereas outcome measurements were collected unilaterally, with each shoulder tested separately. Assessments were performed before and immediately after the warm-up protocol. Outcome measures included shoulder flexion range of motion (ROM), handgrip strength, Closed Kinetic Chain Upper Extremity Stability (CKCUES) performance, and post-warm-up Rating of Perceived Exertion (RPE; Borg CR-10). A significant group-by-time interaction was found for right shoulder flexion ROM (p = 0.003, η²p = 0.346), with a significant increase in the EG from baseline to post-test (p = 0.008). No significant effects were observed for left shoulder flexion ROM, handgrip strength, or CKCUES performance. Post-warm-up RPE was statistically significant in the EG compared to the SWG (p = 0.041). These preliminary findings may suggest the potential practical value of more targeted warm-up strategies in overhead sports, while larger longitudinal studies are needed to confirm their broader functional relevance. Full article

Drying is a critical stage in the postharvest chain, shaping product stability, quality, and economic value. Freshly harvested beans contain high moisture, and inadequate drying can lead to microbial growth, physical deterioration, and loss of key sensory attributes. In recent decades, diverse technologies have been developed to enhance drying efficiency while preserving flavor, improving consistency, and reducing environmental impacts. This review adopts a systematic and comparative approach, synthesizing peer-reviewed literature on conventional practices, advanced solar dryers, mechanical systems, hybrid configurations, and emerging techniques such as microwave, infrared, and desiccant-assisted drying. Emphasis is placed on heat and mass transfer mechanisms, the influence of environmental and operational parameters, and the role of varietal and processing differences. Comparative analyses reveal trade-offs between energy consumption, drying kinetics, and impacts on physical and chemical quality. Sustainability aspects are also examined, including energy use, carbon footprint, water consumption, and scalability for smallholders. Finally, key research gaps are identified, particularly in multiscale modeling, real-time monitoring, and integration with renewable energy and smart control systems. The review highlights pathways for achieving greater consistency, lower environmental burdens, and stronger value chains in producing regions worldwide. Full article

Traditional activated clay (AC) bleaching usually shows limited adsorption selectivity, leading to micronutrient loss during pigment removal, and also suffers from high residual oil retention and poor regenerability. Developing mild bleaching materials with both high adsorption efficiency and selectivity is therefore important for oil refining. Mesoporous Al-MCM-41 (AM) adsorbents with different Si/Al ratios were prepared and characterized in pore structure and acidity, and the bleaching performance against AC in terms of pigment removal and the retention of micronutrients in rapeseed oil and the bleaching mechanism were studied. The results showed that AM25 (Si/Al = 25) exhibited the best overall performance among the AM samples under the tested conditions (70 °C, 20 min). It achieved a bleaching efficiency of 92.3% and removed 94.56% of chlorophyll, 92.94% of lutein, and 84.09% of β-carotene. In addition, AM25 reduced the peroxide value from 2.52 to 0.58 mmol/kg. High retentions of tocopherols (93.89%), phytosterols (98.73%), and squalene (96.32%) were also observed. Meanwhile, the adsorption rates of α-tocopherol, brassicasterol, and α-linolenic acid showed the highest values in their relative homologues of tocopherols, phytosterols, and free fatty acids (FFAs), respectively, due to differences in the methyl amount of tocopherols, the side-chain unsaturation of phytosterols, and the fatty acid chain unsaturation of fatty acids. Furthermore, the kinetic and isotherm data for chlorophyll and carotenoids were better described by the pseudo-second-order and Freundlich models, respectively. Combined with thermodynamic analysis, they indicated that adsorption was a spontaneous, endothermic, entropy-driven, heterogeneous multilayer process dominated by physical adsorption. Further, pigment adsorption was mainly governed by uniform mesopores and Si–OH/Si–OH–Al sites in AM. Among them, carotenoid removal depended primarily on the dispersion effect of moderately strong acid sites within pore-confined regions, whereas chlorophyll removal was more sensitive to the number of acidic sites in AM. AM25 still maintained 83.31% bleaching efficiency after five regeneration cycles. These performances of AM25 are significantly superior to that of AC. Full article

Background: The hallux interphalangeal ossicle (HIO) is commonly considered as an incidental anatomical variant; however, its biomechanical role remains poorly understood. This study aimed to investigate the influence of HIO on hallux joint biomechanics. Methods: A cross-sectional correlational study was conducted, including 419 feet (218 individuals). The presence of HIO was assessed using ultrasound imaging. Range of motion (ROM) of the metatarsophalangeal joint (MTPJ) and interphalangeal joint (IPJ) were evaluated under both open kinetic chain and dynamic conditions. Statistical comparisons between HIO and non-HIO groups were made, and receiver operating characteristic (ROC) curve analysis was used to assess the discriminative capacity of IPJ ROM. Results: HIO was present in 48% of cases and was bilateral in all participants. Individuals with HIO exhibited significantly greater IPJ extension under both open kinetic chain and dynamic conditions (p < 0.05). No significant differences were observed in MTPJ ROM between groups. A positive, albeit variable, relationship was found between ossicle size and IPJ extension. ROC analysis demonstrated moderate discriminative ability of IPJ ROM for detecting HIO (sensitivity 63.2%, specificity 54.6%). Conclusions: The presence of HIO is associated with increased IPJ extension, suggesting a measurable influence on hallux biomechanics. These findings support the notion that the HIO is a biomechanically relevant structure rather than purely incidental an asymptomatic anatomical variant. Increased IPJ extension may represent an early functional adaptation with potential clinical implications. Full article

Crystallization and blockage in tunnel drainage systems represent a major challenge in the operation and maintenance of tunnels in karst regions. This study focuses on a tunnel in Guilin, Guangxi, employing a combined approach of field investigation, laboratory characterization, and molecular dynamics (MD) simulations to explore the atomic-scale mechanism of CaCO₃ crystallization within the drainage system. Field investigations reveal that the groundwater is dominated by Ca²⁺ and HCO₃⁻ ions, and the crystalline products consist primarily of high-crystallinity single-phase calcite, characterized by typical rhombohedral geometric structures and heterogeneous stacking. Molecular dynamics simulations indicate that the CaCO₃ nucleation process is accompanied by the desolvation of Ca²⁺, while background electrolyte ions exert distinct regulatory effects on the nucleation kinetics. SO₄²⁻ participates in cluster construction through strong coordination, inducing the formation of loose, chain-like aggregates; conversely, Cl⁻ delays cluster coalescence primarily through charge shielding and steric hindrance effects. Additionally, Na⁺ influences the overall solution dynamics and the stability of pre-nucleation clusters by constructing stable hydration shells and providing charge neutralization. This research reveals the formation mechanism of tunnel crystallization from a microscopic perspective, providing theoretical support for the prevention and control of crystallization in tunnel drainage systems. Full article

Efficient charge separation and electron transfer in Photosystem II (PSII) depend on small inorganic cofactors that maintain redox balance and catalytic stability. Chloride facilitates water-oxidizing-complex turnover and minimizes charge recombination. Bicarbonate, coordinated to the non-heme iron, facilitates electron transfer between the plastoquinones Q_A and Q_B. This work investigates cooperativity between these cofactors across PSII in the hypercarbonate-requiring cyanobacterium Limnospira maxima. Bromide-for-chloride substitution induces a distinct kinetic limitation at the water oxidizing complex. While bicarbonate depletion inhibits electron transfer at the acceptor side, bromide-substituted cells maintain a measurable level of electron flow through the intersystem chain. The presence of bromide induces structural changes that allow partial electron transfer to continue even in the absence of the bicarbonate cofactor, which is not observed in the chloride system. However, this dual anion stress results in irreversible functional impairment in some centers, whereas full recovery of activity is observed with native chloride. When the donor side is restricted by bromide, the loss of bicarbonate, which is thought to function as a proton buffer for the donor side, compromises the overall stability of the reaction center. This leads to a permanent decrease in activity of the electron transfer chain, suggesting an interdependence between the roles of chloride and bicarbonate that is essential for protecting PSII during ionic stress. Full article

The accumulation of polyethylene (PE) in aquatic ecosystems represents a significant environmental challenge due to the polymer’s high molecular weight and chemical stability. This study investigates the biodegradation potential of Hafnia paralvei UUNT_MP29, a bacterial strain isolated from the gut of common carp (Cyprinus carpio), for low-density polyethylene (LDPE). Initial screening on LDPE-emulsified agar confirmed extracellular enzymatic activity through the formation of distinct clear zones. Quantitative analysis showed a cumulative mass loss of 24.10% by Day 16, with the most intensive degradation occurring between Days 4 and 8, which closely correlated with maximum bacterial count (CFU/mL). Kinetic modeling indicated that the degradation followed a first-order rate law (R² = 0.9269), with a rate constant (k) of 0.2991 days⁻¹ and a remarkably short half-life (t_1/2) of 2.32 days. Structural characterization via FTIR spectroscopy demonstrated oxidative transformation, evidenced by a reduction in sp³ C-H stretching and the emergence of C-O/C-O-C functional groups. SEM micrographs further confirmed extensive bio-deterioration, including surface pitting and macroscale erosion. Thermal analysis (TGA/DTG) supported these findings, showing a significant 10.95 °C decrease in the maximum degradation temperature (T_max), indicating a reduction in polymer chain length. These results suggest that H. paralvei UUNT_MP29 is a highly efficient agent for the rapid breakdown of polyethylene and highlight the potential of aquatic gut microbiota as reservoirs for plastic-degrading biotechnologies. Full article