Search Results (1,297)

L-carnitine is a crucial quaternary ammonium compound widely used in the pharmaceutical, food, and feed industries. Microbial biosynthesis of L-carnitine, compared with chemical synthesis, offers milder conditions, higher stereoselectivity, and a lower environmental impact. However, highly efficient strains and mechanistic insights into the bioconversion of γ-butyrobetaine (γBB) to L-carnitine remain limited. This study focuses on strain WQ-1, a newly screened strain capable of converting γBB to L-carnitine. Based on morphological, physiological, and phylogenetic analyses of 16S rRNA and housekeeping genes, the strain was identified as Ensifer sp. WQ-1. Under the condition of 30 °C, initial pH 8.5, 10% inoculum, 6 g/L initial γBB, shake-flask fermentation reached molar conversion rate of 88%. In a 5 L bioreactor fed-batch fermentation, the L-carnitine titer achieved 13.98 g/L with a 78.7% molar conversion rate. Genomic analysis revealed a 6.97 Mb genome harboring 6568 protein-coding genes, including candidates for quaternary ammonium transport, CoA-dependent transformation, and transcriptional regulation. Comparative transcriptomics identified 58 differentially expressed genes, highlighting the significant upregulation of genes related to acyl-CoA activation, dehydrogenation, carnitine metabolism, and thioester hydrolysis in the presence of γBB. Multi-omics analyses support a putative CoA-dependent metabolic pathway for conversion of γBB to L-carnitine in Ensifer sp. WQ-1. Full article

Accurate prediction of the behavior of alloys and metal matrix composites during high-temperature deformation requires strict consideration of the loading history. To address this problem, a hybrid rheological model for flow stress prediction has been developed, combining a phenomenological description of the yield stress with a recurrent neural network based on the NARX (Nonlinear AutoRegressive with eXogenous inputs) architecture. The memory effect is formed by expanding the input parameters with the response values from the previous step. The identification of the weight coefficients of the NARX neural network is implemented by training an equivalent multilayer perceptron. To improve the generalization ability of the model and eliminate its dependence on a fixed discretization step, the training dataset includes data obtained under non-monotonic changes in the strain rate over time and a variable time interval. The article justifies the structure of the model input parameters, excluding the accumulated strain from the input set due to its lack of informativeness during active softening processes. Verification of the hybrid model on the 7075/2.5% TiC composite in the temperature range of 300–500 °C demonstrated an average relative error of 1.5% when predicting modes that were not involved in the training. The predicted flow stress values fall within the experimental scatter interval of ±5% and accurately reproduce the local features of the flow stress curves. The proposed model and its identification technique provide correct consideration of the deformation history under the complex interaction of hardening and softening processes. Full article

The benefits of legume-nitrogen-fixing bacteria symbioses are vital in agricultural systems globally. Cross-infectivity studies are important for identifying rhizobial strains with potential for use as inoculants. The native rhizobial isolates inoculated on different legume species are the first step to determining host range and ecological adaptive traits. This study reports on the water-use efficiency and mineral nutrition of diverse legume species cross-inoculated by native rhizobial isolates from Eswatini, Ghana and South Africa under glasshouse conditions. A portable infrared red gas analyzer was used for water use efficiency. Data from a gas exchange study shows that rhizobial strains can significantly influence the photosynthetic functioning of their host plants. As a result, photosynthetic rates differed depending on bacterial compatibility with the host plant, as well as its symbiotic efficacy. Isolate TUTGmGH2 induced greater accumulation of P, K, Mg, Zn, Cu and Mn in soybean and Winged bean, clearly suggesting that rhizobia do have an influence on the mineral nutrition of their host plants. Therefore, these findings further show that native rhizobial isolates can be manipulated to enhance mineral nutrient uptake, promote growth and development and also produce nutrient-dense food with a low environmental impact globally since rhizobia do have an influence on the mineral nutrition of their host plants. Full article

Within the framework of elastoplastic theory, this study develops and improves a fractional cyclic constitutive model capable of describing rate-dependent ratcheting behavior by defining the ratcheting parameter as a function of the cumulative plastic strain rate and describing the plastic strain rate and back stress in fractional-order forms. Additionally, a brief introduction is provided on the numerical implementation process and parameter determination method of this model. The newly improved fractional-order model was subsequently employed to simulate and predict the cyclic deformation of the cyclically softening material, EA4T axle steel. The following conclusions can be drawn: owing to the incorporation of fractional calculus, the newly improved model can predict both the monotonic tensile curves and the cyclic softening behavior of materials under different strain rates—capabilities that are not achievable with conventional elastic–plastic cyclic constitutive models. By defining the ratcheting parameter as a function of the cumulative plastic strain rate, the improved fractional model can reasonably predict the evolution laws of both uniaxial and non-proportional multiaxial ratcheting. By describing the evolution of plastic strain rate and back stress in fractional-order forms, the newly improved fractional model can provide a relatively accurate prediction of the rate-dependent uniaxial and multiaxial ratcheting behaviors. Full article

Kluyveromyces marxianus is a non-conventional yeast capable of efficiently metabolizing lactose, but acetate can inhibit its growth. Because K. marxianus strains differ physiologically, their tolerance to acetate also varies. Acetate tolerance was investigated in four K. marxianus strains grown on glucose, lactose, and an equimolar mixture of glucose and galactose. The inhibitory effect of 40 mM acetate on growth was evaluated at pH 4.5–6.0 by using acetate and citrate buffer systems. In lactose-containing media at pH 4.5, the strongest inhibition was observed in strain NCYC 2791, whose specific growth rate decreased from 0.51 ± 0.01 h⁻¹ to 0.13 ± 0.01 h⁻¹, while lag-phase duration increased from 10.11 ± 0.35 h to 21.09 ± 1.95 h. In contrast, DSM 5422 showed a smaller decrease in specific growth rate, from 0.54 ± 0.03 h⁻¹ to 0.31 ± 0.06 h⁻¹. NCYC 2791 also reached only OD600 = 0.18 after 45 h in acetate-containing lactose media, whereas the other three strains reached approximately OD600 = 0.6. The distribution of cytosolic and non-cytosolic β-galactosidase activity differed among strains, with the highest proportion of cytosolic activity in NCYC 2791 (80% of total activity). A significant positive correlation was found between the proportion of cytosolic β-galactosidase and the degree of growth inhibition by acetate at pH 4.5 (Pearson r = 0.9967, p = 0.0033). These findings suggest that strain-dependent β-galactosidase localization may be related to acetate tolerance, although this association should be interpreted cautiously because localization was not measured under acetate stress conditions. Full article

Background: Acute myocardial infarction (AMI) in younger adults represents a distinct clinical entity with biological features that may differ from those observed in later-onset disease. We aimed to characterize age-dependent clinical, inflammatory, lipid, and echocardiographic phenotypes and to explore their association with in-hospital adverse clinical events. Methods: In this prospective, single-center, age-stratified observational study conducted between 20 January 2024 and 20 January 2025, 90 patients with AMI undergoing successful percutaneous coronary intervention (PCI) were selected from 1051 AMI admissions: 30 aged 25–44 years and 60 aged ≥45 years. Admission biomarkers (including C-reactive protein, leukocyte-derived indices, and lipid parameters) and echocardiographic variables (left ventricular ejection fraction and global longitudinal strain) were assessed, and exploratory receiver operating characteristic analyses were performed for in-hospital adverse clinical events. Results: Younger patients demonstrated a predominantly atherogenic profile, with higher smoking prevalence (63.3% vs. 13.3%; p < 0.001) and markedly higher lipoprotein(a) concentrations (76.18 ± 10.10 vs. 17.61 ± 11.42 mg/dL; p < 0.001). Older patients exhibited higher inflammatory indices (NLR and SII), higher hs-cTnI and NT-proBNP concentrations, and worse ventricular function. STEMI predominated in both age groups (83.3% in each), and infarct localization did not differ significantly between younger and older patients. The rate of in-hospital adverse clinical events was numerically higher in older patients (18.3% vs. 10.0%), but this difference was not statistically significant. In exploratory ROC analyses, CRP (AUC = 0.874) and LVEF (AUC = 0.868) showed the highest discriminatory performance. Conclusions: AMI appears to manifest through age-related baseline phenotypes: a more atherogenic/thrombotic profile in younger patients and a more inflammatory/ventricular dysfunction profile in older patients. CRP and LVEF emerged as the strongest exploratory discriminators of in-hospital adverse clinical events, but these findings require validation in larger cohorts. Full article

Deep rock engineering faces the combined challenges of high in situ stress and dynamic disturbances. However, traditional constitutive models treat confining pressure and rate effects independently, leading to significant prediction errors under high confinement, and the underlying coupled mechanisms remain insufficiently understood. To address this, dynamic tests were conducted using an active confining pressure SHPB system under hydrostatic pressures of 0–30 MPa and loading rates of 2000–12,000 GPa·s⁻¹, with simultaneous acoustic emission and dissipated energy monitoring. A confining pressure-sensitive rate-dependent dual-scalar damage constitutive model was established, innovatively incorporating a Constraint Intensification Factor (CIF) and a viscous regularization technique to intrinsically couple confinement and rate effects. The results reveal a synergistic strengthening effect between confining pressure and loading rate, with higher confining pressure enhancing rate sensitivity. The proposed model accurately captures the elastic, peak, and post-peak segments of stress–strain curves, with peak stress errors below 5%, effectively overcoming the prediction deficiencies of traditional models under high confining pressures. These findings provide critical parameters and a reliable theoretical basis for deep rock engineering design. Full article

Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating wheat disease leading to significant yield loss and mycotoxin contamination. This study elucidated the biocontrol mechanism of Bacillus velezensis 20507 fermentation broth against FHB during wheat infection. The broth exhibited strong, time-dependent antifungal activity in vitro, with optimal growth suppression (inhibition rates up to 75%) achieved using broth fermented for 3–7 days. In planta experiments confirmed its efficacy in alleviating disease symptoms. Employing a dual RNA-seq strategy, we analyzed the tripartite interaction between the biocontrol agent, pathogen, and wheat host. Transcriptomic analysis revealed that the broth directly suppressed the pathogen, causing 1510 differentially expressed genes (DEGs, predominantly down-regulated) and disrupting pathways related to carbohydrate metabolism and cell wall integrity. In wheat, the fermentation broth of B. velezensis 20507 counteracted F. graminearum infection by reprogramming the host transcriptome. KEGG analysis during co-inoculation showed that the broth up-regulated defense-related pathways involved in energy, hormone signaling, and cellular maintenance, while down-regulating primary metabolic pathways, indicating a resource reallocation strategy. Furthermore, transcriptomic analysis revealed that the broth alone primed the wheat defense system, and this primed state significantly enhanced the defense response upon pathogen challenge. Untargeted metabolomics identified key antimicrobial compounds, including lipopeptides and the macrolide Macrolactin A. Bioassay-guided fractionation isolated two active fractions (Fr A and Fr B) with potent antifungal activity. This integrated multi-omics study demonstrates that B. velezensis 20507 combats FHB through a coordinated dual mechanism: direct inhibition of the fungus via specific metabolites like Macrolactin A, and simultaneous reprogramming of the host defense and metabolic landscape. These findings provide a scientific foundation for developing this strain as an effective biocontrol agent. Full article

Hybrid polymeric woven composites (HPWCs) are increasingly important in automotive, aerospace, and renewable energy structures where low weight, impact tolerance, damage containment, and superior mechanical properties are required. By combining dissimilar fibres within woven architectures, HPWCs can achieve a more favourable balance of stiffness, strength, and energy absorption than single-fibre woven systems; however, experimental evidence and predictive modelling remain insufficiently integrated, particularly under dynamic and post-impact loading. This systematically searched critical review provides an HPWC-focused synthesis that links architecture-driven mechanical behaviour, damage development, and multiscale numerical simulation within a single framework. The effects of reinforcement architecture, fibre pairing, and matrix selection on tensile, flexural, compressive, interlaminar, strain rate-dependent, and impact responses are examined, with particular emphasis on barely visible impact damage and post-impact residual strength. Macroscale, mesoscale, and microscale finite element strategies are critically compared in terms of predictive fidelity, computational cost, and suitability for design-orientated assessment. The main contribution of this review lies in integrating experimental characterisation with modelling limitations, validation requirements, and industrial relevance, thereby clarifying where current approaches are effective and where critical gaps remain. Practical implications for lightweight structural design, impact-resistant components, and future validation-driven research are highlighted. Full article

The residual mechanical properties after fire exposure form the basis for evaluating the structural performance of aluminium alloy components subjected to fire without collapse. This research investigated the impact of low cooling rates on the residual mechanical properties of 6063-T5 aluminium alloy after various cooling methods were utilized. A total of 48 tensile specimens were subjected to controlled elevated temperatures (ETs) ranging from 200 to 500 °C for 30 min soaking, followed by two cooling regimes: cooling in air (CIA) and cooling in furnace (CIF). For both CIA and CIF conditions, an increase in ETs led to a gradual increase in ductility, particularly elongation at fracture. Moreover, the effects of ETs on the fracture performance were discussed. Key mechanical parameters—namely nominal yield strength, ultimate tensile strength, elastic modulus, and strain at ultimate strength—were quantified across ETs and cooling methods, which were compared among different aluminium alloys. Empirical predictive equations were developed to capture the temperature-dependent degradation trends of mechanical properties, and a plasticity Ramberg–Osgood model was proposed and validated against test data. The metallographic microstructure of 6063-T5 aluminium alloy after different ETs revealed that the evolution of precipitate was the primary contributor to strength degradation. Finally, finite element simulations of aluminium plate girders after various ETs were conducted, which incorporated the proposed constitutive model and replicated the degradation trends observed in tensile tests. These findings provide a reliable foundation for implementing the proposed model into finite element simulations and structural assessment tools for post-fire aluminium alloy structures. Full article

Background: Operational performance in security-force settings depends on maintaining accurate motor–cognitive and shooting performance under acute physical strain. This descriptive pilot study examined pre–post performance patterns during a fixed-order acute-load protocol and explored whether trial-level and spatial analyses identified changes beyond aggregate scores. Methods: Nineteen applicants (10 men, 9 women; 21.6 ± 1.0 years) completed two testing sequences separated by one week. All participants completed Sequence 1 first and Sequence 2 second; therefore, sequence-related observations were interpreted descriptively rather than causally. In both sequences, participants performed Hawk Eye testing, IPSC-based shooting, and the Jaciak Motor Coordination Test, with the order of Hawk Eye and shooting reversed between sequences. Primary outcomes were first-shot hit rate and Hawk Eye error count. Secondary and exploratory outcomes included shooting miss rate and time, Hawk Eye stimulus time, minimum and maximum response times, trial-level timing, spatial distributions, and cross-task coupling. Results: Heart rate increased markedly after the Jaciak test in both sequences, with end-of-test values corresponding to approximately 86–88% of age-predicted HRmax. Model-based analysis indicated lower post-load odds of a first-shot hit compared with pre-load performance. In contrast, no detectable pre–post change was observed for Hawk Eye error probability. Descriptively, first-shot hit rate decreased in Sequence 1 (62.1 ± 19.9% vs. 42.1 ± 28.2%; p = 0.029), while the decrease in Sequence 2 was smaller and not statistically significant (61.1 ± 24.5% vs. 52.6 ± 28.4%; p = 0.267). Hawk Eye error count showed no statistically detectable pre–post change in either sequence, although maximum response time decreased in Sequence 1 (p = 0.008). Trial-level and spatial analyses indicated additional temporal and location-specific patterns, but exploratory cross-task spatial associations were inconsistent. Conclusions: In this fixed-order descriptive pilot study, post-load testing was associated with lower first-shot shooting performance in this sample, whereas no statistically detectable deterioration was observed for Hawk Eye error probability. However, because the design lacked a no-load control condition and all participants completed the same sequence order, the observed pre-to-post differences cannot be attributed specifically to acute physical load. They should be interpreted as descriptive performance patterns within the implemented protocol. Full article

Colorectal cancer (CRC) is a digestive tract malignant tumor with a relatively high incidence and mortality rate worldwide. The occurrence and development of CRC are closely associated with disturbances in the gut microbiota. Paraclostridium tenue (synonym Eubacterium tenue) is generally considered a harmless commensal and can be isolated from fecal samples of healthy adults. However, whether this bacterium is a beneficial organism with an antitumor effect is unknown. This study systematically evaluated the anti-CRC effects of P. tenue strain Pt517 on CRC cells in vitro and in the CT26 syngeneic mouse model. Pt517 culture supernatant (Pt517CS) inhibited the proliferation, colony formation, and migration ability of CRC cells; induced cell apoptosis; and altered cell cycle distribution. Daily intragastric administration of Pt517 significantly inhibited tumor growth in mice; increased the expression levels of TNF-α, INF-γ, and CD8 in tumor tissues; and decreased the levels of IL-6, IL-10, and TGF-β. Pt517 intervention significantly modulated the gut microbiota composition with increased relative abundance of Parabacteroides goldsteinii, Lachnospiraceae, and Enterorhabdus caecimuris B7. The long-chain fatty acids (LCFAs), stearic acid and palmitic acid, were increased in the serum of treatment group mice and detected in Pt517CS. Functional verification indicated that stearic acid and palmitic acid directly inhibited the proliferation of CT26 cells in a dose-dependent manner, suggesting that Pt517 might exert its anti-CRC effect by secreting LCFAs. These findings indicate that P. tenue Pt517 is a potential new candidate for the microbial treatment of CRC, which warrants further validation for its safety and efficacy before clinical translation. Full article

The Low-Strain Pile Integrity Test (LSPIT), standardized in ASTM D5882, is widely used as a rapid and economical non-destructive technique for assessing pile continuity in deep foundation systems. However, interpretation of LSPIT reflectograms remains strongly dependent on expert judgment and is influenced by soil–pile interaction effects such as damping and radiation losses, which can alter waveform morphology and confound automated defect screening. This study proposes a soil-aware deep learning framework that combines image-based reflectogram features with categorical geotechnical context describing the dominant soil regime at the measurement site. Reflectogram images are processed with a pretrained ConvNeXt-Large backbone, while soil information derived from Unified Soil Classification System (USCS) logs is represented as a categorical auxiliary input and mapped to a learnable embedding. The resulting multimodal design conditions waveform interpretation based on site context rather than relying on signal morphology alone. The framework is examined on an assembled benchmark of 510 expert-labeled reflectograms (404 intact and 106 defective), including a nine-site subset of 182 field records with explicit soil annotations. On the assembled benchmark, the model yields 99.41% accuracy and a weighted F1-score of 0.9941; on the nine-site subset, the observed accuracy is 99.45% with zero missed defective cases. Balanced accuracy, specificity, missed-detection rate, false-alarm rate, and confidence intervals are additionally reported to better align the evaluation with engineering screening practice. The study also states the current limits of the evidence base, including partial soil annotation, dominant-soil simplification, restricted soil coverage, and the absence of leave-site-out and interpretability-focused validation. Overall, the results support soil-aware multimodal learning as a promising proof-of-concept direction for more context-aware automated LSPIT interpretation, while also identifying the validation steps still required for broad field deployment. Full article

Operando mechanical behavior of lithium-ion batteries under aggressive conditions remains insufficiently quantified, especially under combined high-rate and deep-discharge operation. This study investigated strain evolution in a commercial 18650 NMC lithium-ion cell using surface-mounted fiber Bragg grating sensors across 20 sequential conditions combining five discharge rates (1–4.5 C) and four cutoff voltages (2.5–1.0 V). All tests were performed on a single cell using identical 0.5 C constant-current constant-voltage charging, followed by a 2 h rest period and controlled discharge, to systematically evaluate mechanochemical evolution with increasing electrochemical severity. Maximum tensile strain during charging ranged from 45 to 59 µε and showed limited sensitivity to discharge severity. In contrast, discharge behavior exhibited clear rate- and cutoff-dependent transitions from tensile to compressive deformation; the most severe condition (4.5 C, 1.0 V cutoff) produced a peak compressive strain of about −27 µε and the most negative residual strain after relaxation. Although temperature increased monotonically with C-rate, strain evolution was nonlinear and non-monotonic, indicating that electrochemically induced stress dominated over thermal expansion alone. These findings reveal progressive amplification of irreversible deformation under severe discharge and demonstrate the value of fiber Bragg grating sensing for operando assessment of electrochemical–mechanical coupling in cylindrical lithium-ion cells. Full article

Hydrogen-enriched fuel injection in staged gas-turbine combustors is commonly achieved through jet-in-crossflow (JICF) configurations, where flame stabilization is governed by a local balance between flow-induced strain/mixing and chemical reaction rates. This work investigates turbulent reacting JICF relevant to staged combustion conditions using high-fidelity simulations with adaptive mesh refinement (AMR) and differential-diffusion effects together with Lagrangian particle statistics. Chemistry model uncertainties are incorporated by using a projection method that maps uncertainty estimates from detailed mechanisms into the model used in this work. Results show that the macroscopic flame topology remains in a stable two-branch regime (lee-stabilized and lifted) and is primarily controlled by the jet momentum–flux ratio J. Visualization of the normalized scalar dissipation rate reveals that the flame front resides on the low-dissipation side of intense mixing layers, occupying an intermediate region between over-strained and under-mixed regions. While hydrogen content does not significantly change the global stabilization mode for the cases studied, uncertainty analysis reveals composition-dependent differences that are not apparent in the mean behavior alone. In particular, visualization in Eulerian (χ, T) state-space analysis and particle statistics conditioned on the stoichiometric surface demonstrate that higher-hydrogen cases observe a lower scalar dissipation rate and exhibit substantially reduced variability in OH production under kinetic-parameter perturbations, whereas lower-hydrogen blends experience higher dissipation and amplified chemical sensitivity. These findings highlight that, even in globally similar JICF regimes, the hydrogen content can modify the local response of the flame to kinetic-parameter uncertainty, motivating uncertainty-aware interpretation and design for hydrogen-fueled staging systems. Full article