Search Results (2,227)

The deformation mechanism during the hot compression of PM nickel-based superalloy FGH99 and its micro-structural evolution, especially the evolution of γ’ phases, are the key factors affecting the final molding quality of aero-engine hot forged turbine disks. In this study, a new constitutive model of viscoplasticity with micro-structures as physical internal parameters were developed to simulate the hot compression behavior of FGH99 by incorporating the strengthening effect of the γ’ phase. The mechanical behavior of high-temperature (>1000 K) compressive deformation of typical superalloys under a wide strain rate (0.001~1 s⁻¹) is investigated using the Gleeble thermal-force dynamic simulation tester. The micro-structure after the hot deformation was characterized using EBSD and TEM. Work hardening as well as dynamic softening were observed in the hot compression tests. Based on the mechanical responses and micro-structural features, the model considered the coupled effects of dislocation density, DRX, and γ’ phase during hot flow. The model is programmed into a user subroutine based on the Fortran language and called in the simulation of the DEFORM-3D V6.1 software, thus realizing the multiscale predictive simulation of FGH99 alloy by combining macroscopic deformation and micro-structural evolution. The established viscoplastic constitutive model shows a peak discrepancy of 10.05% between its predicted hot flow stresses and the experimental values. For the average grain size of FGH99, predictions exhibit an error below 7.20%. These results demonstrate the high accuracy of the viscoplastic constitutive model developed in this study. Full article

This study considered and compared silver, gold, and their combination of nanoparticles (AgNPs, AuNPs, and Au-AgNPs) with biocompatible material mesoporous silica SBA-15 as potential antibacterial agents. A facile, one-pot “green” methodology, utilizing L-histidine as a reducing agent and bridge between components, was employed to obtain Ag@SBA-15, Au@SBA-15, and Au-Ag@SBA-15 nanocomposites without the use of external additives. Various physicochemical tools (UV-Vis, TEM, SAED, FESEM, XPS, BET, XRD, and FTIR) presented SBA-15 as a good carrier for spherical AgNPs, AuNPs, and Au-AgNPs with average diameters of 8.5, 16, and 9 nm, respectively. Antibacterial evaluations of Escherichia coli and Staphylococcus aureus showed that only Ag@SBA-15, at a very low Ag concentration (1 ppm) during 2 h of contact, completely reduced the growth (99.99%) of both strains, while the Au@SBA-15 nanocomposite required higher concentrations (5 ppm) and time (4 h) to reduce 99.98% E. coli and 94.54% S. aureus. However, Au introduction in Ag@SBA-15 to form Au-Ag@SBA-15 negatively affected its antibacterial potential, lowering it due to the galvanic replacement reaction. Nevertheless, the rapid and effective combating of two bacteria at low NPs concentrations, through the synergistic effects of mesoporous silica and AgNPs or AuNPs, in Ag@SBA-15 and Au@SBA-15 nanocomposites, provides a potential substitute for existing bacterial disinfectants. Full article

Galls of the Cynipidae, such as the Knopper gall, are abnormal plant outgrowths induced by insect activity. These structures not only protect the developing larvae but also alter the biochemical properties of host plant tissues. In this study, we report the green synthesis of silver nanoparticles (AgNPs) using ethanolic extracts of Quercus robur Knopper galls. AgNPs were synthesized via reduction of AgNO₃ and characterized using ATR-FTIR analysis, UV-Vis spectrophotometry, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). The UV-Vis analysis showed a strong surface plasmon resonance (SPR) peak at 418 nm. A face-centered cubic (fcc) crystalline structure with an average crystallite size of about 12 nm was verified by PXRD patterns. TEM imaging revealed well-dispersed spherical nanoparticles, consistent with the size obtained via PXRD. ATR-FTIR analysis indicated the involvement of polyphenolic and protein-related functional groups in reduction and stabilization. The synthesized AgNPs exhibited strong growth inhibition capacity against B. subtilis and S. aureus, and moderate capacity against E. coli and P. aeruginosa. These findings highlight the potential of Knopper gall extract as a sustainable source for the eco-friendly synthesis of biologically active nanoparticles. Full article

In this paper, silver oxide (AgO) and copper oxide (CuO) coatings are placed on a single sputtering target with the direct-current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HIPIMS) methods. All the tested coatings are obtained in a reactive process using a metallic target made by the Kurt Lesker company. The investigated coatings are deposited at room temperature on substrates made of pure iron (ARMCO) and polypropylene (PP) without substrate polarization. The deposition time for all the coatings is the same. The results of SEM and TEM investigations clearly show that using the HIPIMS method for the deposition of AgO and CuO coatings reduces their thickness and increases their structure density. Coatings produced with the HIPIMS method are characterized by a higher hardness and Young’s modulus. The value of hardness for AgO and CuO coatings deposited by the HIPIMS method is around 50% higher for AgO coatings and around 24% higher for CuO coatings compared to the coatings obtained by the DC method. This is also true of Young’s modulus values, which are around 30% higher for AgO coatings and 15% higher for CuO coatings produced by the HIPIMS method compared to those of coatings obtained with the DC method. AgO and CuO coatings deposited with both the methods (HIPIMS and DCMS) showed 100% reduction in the viability of two reference laboratory bacteria strains—Escherichia coli (Gram−) and Staphylococcus aureus (Gram+)—on both types of substrates. Additionally, these coatings are characterized by their hydrophobic properties, which means that they can create a protective barrier, making it difficult for bacteria to stick to the surface, limiting their development and preventing the phenomenon of biofouling. The HIPIMS technology allows for the deposition of coatings with better mechanical properties than those produced with the DCMS method, which means that they are more resistant to brittle fractures and wear and have very good antimicrobial properties. Full article

This study presents a sustainable upcycling strategy to convert “Pit,” a carbon-rich coke oven by-product from steel manufacturing, into high-purity graphite for use as an anode material in lithium-ion batteries. Despite its high carbon content, raw Pit contains significant impurities and has irregular particle morphology, which limits its direct application in batteries. We employed a multi-step, additive-free refinement process—including jet milling, spheroidization, and high-temperature graphitization—to enhance carbon purity and structural properties. The processed Pit-derived graphite showed a much-improved particle size distribution (D50 reduced from 25.3 μm to 14.8 μm & Span reduced from 1.72 to 1.23), increased tap density (from 0.54 to 0.80 g/cm³), and reduced BET surface area, making it suitable for high-performance lithium-ion batteries anodes. Structural characterization by XRD and TEM confirmed dramatically enhanced crystallinity after graphitization (graphitization degree increasing from ~13 for raw Pit to 95.7% for graphitized Pit at 3000 °C). The fully processed graphite (denoted S_Pit3000) delivered a reversible discharge capacity of 346.7 mAh/g with an initial Coulombic efficiency of 93.5% in half-cell tests—comparable to commercial artificial graphite. Furthermore, when composited with silicon oxide to form a hybrid anode, the material achieved an even higher capacity of 418.0 mAh/g under high mass loading conditions. These results highlight the feasibility of transforming industrial coke waste into value-added electrode materials through environmentally friendly physical processes. The upcycled graphite anode meets industrial performance standards, demonstrating a promising route toward circular economy solutions in both the steel and battery industries. Full article

This study aimed to investigate the histological features of the intestine of Acipenser dabryanus from 1 to 15 months of age via HE staining, AB-PAS staining, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The intestine of A. dabryanus comprises the duodenum, spiral valve intestine, and rectum. With age, the duodenal diameter and mucosal/muscular layer thickness increased, the spiral valve intestine’s mucosa thickened and protrusions formed networks, and the rectal diameter enlarged. Abundant mucus cells, predominantly type IV, were found in the duodenum, spiral valve intestine, and rectum of A. dabryanus at different ages by AB-PAS staining. Our study confirmed the presence of ciliated columnar cells (with ‘9 + 2’ cilia structure) with orderly arranged cilia at their apices in the mucosal epithelium of A. dabryanus’s duodenum, spiral valve intestine, and rectum for the first time, as shown by SEM and TEM. The presence of spiral valves and ciliated columnar cells in the intestinal structure of A. dabryanus highlights its unique features and evolutionary significance. These findings highlight A. dabryanus’s unique intestinal features and evolutionary significance, providing a basis for scientific feed formulation and enhancing our understanding of the histological characteristics of the sturgeon intestine. Full article

Glottic insufficiency, often caused by laryngeal nerve injury, impairs voice quality and breathing. Current treatments, such as hyaluronic acid injection, require frequent reapplication every 3–6 months. This study aimed to investigate the therapeutic potential of small extracellular vesicles (sEVs) derived from Wharton’s Jelly mesenchymal stem cells (WJMSCs) incorporated into genipin-crosslinked gelatin hydrogels (GCGHs) for promoting vocal fold fibroblast (VFFs) regeneration in vitro. WJMSCs were isolated from umbilical cords, expanded to passage 4, and used for sEV isolation via tangential flow filtration (TFF). The sEVs (585.89 ± 298.93 µg/mL) were characterized using bicinchoninic acid assay (BCA), nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western blot. Seven concentrations of sEVs were tested on VFFs to evaluate cytotoxicity and proliferation, identifying 75 µg/mL as the optimal dose. GCGHs were then combined with WJMSCs and sEVs and evaluated for physicochemical properties, degradation, biocompatibility, and immune response. The hydrogels were injectable within 20 min and degraded in approximately 42 ± 0.72 days. The optimal sEV concentration significantly enhanced VFFs proliferation (166.59% ± 28.11) and cell viability (86.16% ± 8.55, p < 0.05). GCGH-MSCs showed the highest VFFs viability (82.04% ± 10.51) and matrix contraction (85.98% ± 1.25) compared to other groups. All hydrogel variants demonstrated minimal immune response when co-cultured with peripheral blood mononuclear cells (PBMCs). GCGH is a promising scaffold for delivering WJMSCs and sEVs to support VFF regeneration, with demonstrated biocompatibility and regenerative potential. Further in vivo studies are warranted to validate these findings. Full article

Under the combined influence of global climate change and intensified human activities, ecosystem services (ESs) are undergoing substantial transformations. Identifying their nonlinear driving mechanisms is crucial for promoting regional sustainable development. Taking Anhui Province as a case study, this research evaluates the spatial patterns and temporal dynamics of six key ecosystem services from 2000 to 2020—namely, biodiversity maintenance (BM), carbon fixation (CF), crop production (CP), net primary productivity (NPP), soil retention (SR), and water yield (WY). The InVEST and CASA models were employed to quantify service values, and the XGBoost–SHAP framework was used to reveal the nonlinear response paths and threshold effects of dominant drivers. Results show a distinct “high in the south, low in the north” spatial gradient of ES across Anhui. Regulatory services such as BM, NPP, and WY are concentrated in the southern mountainous areas (high-value zones > 0.7), while CP is prominent in the northern and central agricultural zones (>0.8), indicating a clear spatial complementarity of service types. Over the two-decade period, areas with significant increases in NPP and CP accounted for 50% and 64%, respectively, suggesting notable achievements in ecological restoration and agricultural modernization. CF remained stable across 98.3% of the region, while SR and WY exhibited strong sensitivity to topography and precipitation. Temporal trend analysis indicated that NPP rose from 395.83 in 2000 to 537.59 in 2020; SR increased from 150.02 to 243.28; and CP rose from 203.18 to 283.78, reflecting an overall enhancement in ecosystem productivity and regulatory functions. Driver analysis identified precipitation (PRE) as the most influential factor for most services, while elevation (DEM) was particularly important for CF and NPP. Temperature (TEM) and potential evapotranspiration (PET) affected biomass formation and hydrothermal balance. SHAP analysis revealed key threshold effects, such as the peak positive contribution of PRE to NPP occurring near 1247 mm, and the optimal temperature for BM at approximately 15.5 °C. The human footprint index (HFI) exerted negative impacts on both BM and NPP, highlighting the suppressive effect of intensive anthropogenic disturbances on ecosystem functioning. Anhui’s ES exhibit a trend of multifunctional synergy, governed by the nonlinear coupling of climatic, hydrological, topographic, and anthropogenic drivers. This study provides both a modeling toolkit and quantitative evidence to support ecosystem restoration and service optimization in similar transitional regions. Full article

Pseudomonas aeruginosa is an opportunistic pathogen of public health concern. This study aimed to investigate the prevalence of P. aeruginosa, some virulence factors, and antimicrobial resistance patterns and highlight the potential pathways of horizontal bla_SHV-resistant gene transfer from diverse sources. A total of 220 samples were collected from fish (n = 90), water (n = 30), poultry (n = 50), and humans (n = 50). All samples were isolated, confirmed by the Vitek 2 system, and tested against antimicrobial agents. Some virulence and resistance genes were examined by PCR and sequenced for the bla_SHV-resistant gene from four selected isolates from each source. SPSS v26, with chi-squared tests and Pearson correlations (p < 0.05), was implemented for statistical investigation. P. aeruginosa was isolated at 33.3%, 20%, 14%, and 24% from fish, water, poultry, and humans, respectively. Using the diffusion disk method, extensively drug-resistant (XDR) and multidrug-resistant (MDR) strains were detected. All strains harbored the oprL and toxA genes, while the lasB gene was present in 40% of fish samples but not present in human samples. All strains lacked the exoS gene. The tetA, sul1, bla_SHV, and bla_TEM resistance genes were detected at different percentages. The bla_SHV genes from fish and water isolates were closely related to each other and showed similarity to those of the human isolates. The poultry isolates formed a separate phylogenetic lineage. The emergence of XDR and MDR P. aeruginosa highlights a possible public health threat. Based on the gene similarity between fish and water isolates, our results suggest that these isolates have a common origin. The similarity between the human isolates and environmental isolates (fish and water) raises concerns about possible transmission to humans. Full article

Background: Stannous ions and polyphenols are effective substances in preventive dentistry. The present study’s aim was to investigate whether a combination of these substance groups can achieve increased efficacy. Methods: Initial biofilm formation was performed on bovine enamel slabs, carried by 10 subjects intraorally. The subjects rinsed with tannic acid, SnCl₂, SnF₂, a combination (50:50) of tannic acid and SnCl₂, or a combination of tannic acid and SnF₂, with no rinsing in the negative control. Bacterial adherence, glucan formation (8 h, 48 h oral exposition,) and calcium release kinetics were measured (pH 2; 2.3; 3). Statistics were performed with the Kruskal–Wallis test (p < 0.05), Mann–Whitney U test (p < 0.05), and Bonferroni–Holm correction. Results: All rinsing solutions reduced bacterial adherence by more than 50%. Initial bacterial colonization and glucan formation was significantly reduced by SnF₂ and SnCl₂ as well as their combinations with tannic acid. The most significant reductions in calcium release at pH 2; 2.3; and 3 were obtained by SnF₂ and the combination of SnF₂ and tannic acid. At the acidic pH 2.0, SnF₂, SnCl₂, and tannic acid and SnF₂ showed significant protection compared to the control (p ≤ 0.01). TEM micrographs indicated that rinsing with SnF₂ and tannic acid leads to pronounced electron dense, thick pellicle layers. Conclusions: SnCl₂ and SnF₂, as well as their combinations with tannic acid, led to a reduction in initial bacterial colonization and glucan formation, showing an erosion-protective effect. These findings confirm the clinical applicability hitherto suspected by in vitro findings. Full article

In this study, COOH-functionalized co-polymer of acrylonitrile and itaconic acid (P(AN-co-IA)) is synthesized via free radical copolymerization using DMSO as solvent. The continuous non-aligned carbon nanofibers (CNFs) with different amounts of metallocene (zirconocene and ferrocene) are fabricated through electrospinning, followed by a series of heat treatments under an inert atmosphere. The influence of metallocenes on electrospun carbon nanofiber diameter, alignment, and structural ordering was systematically investigated using FESEM, XRD, Raman spectroscopy, and TEM. Incorporation of dual metallocenes significantly alters the fiber diameter, improves orientation, and promotes graphitic domain formation at 1100 °C, a much lower temperature than conventional graphitization. The optimized sample (Zr-Fe)₁-P(AN-co-IA)-eGNF) exhibited the lowest I_D/I_G ratio compared to pristine and all prepared samples, indicating an improved degree of graphitization due to the uniform distribution of metallocene nanofiber matrix. Furthermore, the electrical conductivity of optimized (Zr-Fe)₁-P(AN-co-IA)-eGNF reached the highest value (1654.5 S/m) due to the high degree of graphitization of carbon nanofibers. These results show that integrating dual metallocene is an efficient pathway for tailoring nanofiber morphology and achieving conductive, structurally ordered electrospun eGNFs at reduced temperatures, with potential applications in various fields. Full article

The lodging of wheat has a significant impact on its yield, and its resistance is intricately associated with the mechanical strength of its stem. The majority of existing studies on this issue have been conducted at the macroscale, and the quantitative relationship between cellular structural characteristics and the mechanical strength of the wheat stem remains poorly understood. This study aimed to investigate this relationship in two wheat cultivars: ‘Zhoumai 36’ and ‘Angong 38’. Samples were collected from the second basal internode of stems at three growth stages: anthesis, grain filling, and maturity. Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) were utilized to examine cellular morphology, measure cell wall thickness, and analyze microfibril angles and crystallite sizes within the cell walls. Tensile tests were conducted to determine the tensile strength and elastic modulus of the stem samples. The relationship between cellular structural characteristics and stem mechanical strength was systematically investigated. The results demonstrated that during the developmental transition from anthesis to maturity, the elastic modulus of the stems in the two wheat varieties exhibited divergent trends: a decrease from 1.60 ± 0.08 GPa to 1.25 ± 0.04 GPa (mean ± SEM) in ‘Zhoumai 36’ and an increase from 1.15 ± 0.07 GPa to 1.48 ± 0.18 GPa (mean ± SEM) in ‘Angong 38’ These differences were accompanied by variations in water content between the two varieties. Furthermore, it was observed that the thickness of the S2 layer (the middle layers of the secondary cell wall) in both sclerenchyma and vessel cells showed a positive correlation with stem elastic modulus. Conversely, the microfibril angle of the S2 layer displayed a negative correlation with elastic modulus. Cellulose crystallite size varied across the growth stages, ranging from 1.22 ± 0.10 nm to 1.83 ± 0.30 nm (mean ± SEM) in ‘Zhoumai 36’ and from 1.42 ± 0.11 nm to 1.85 ± 0.23 nm (mean ± SEM) in ‘Angong 38’, respectively, and this parameter also exhibited a positive correlation with elastic modulus. This study clarified the variation trends of stem elastic modulus in wheat cultivars ‘Zhoumai 36’ and ‘Angong 38’ from anthesis to maturity and revealed, through experimental determination and correlation analysis, the microscale quantitative relationships between the stem cellular structural characteristics (S2 layer thickness, S2 layer microfibril angle, and cellulose crystallite size) and mechanical strength (characterized by elastic modulus) in the two cultivars. Full article

Typhoid fever, caused by Salmonella enterica subsp. enterica serovar Typhi (S. typhi), remains a major public health concern, particularly in low-resource settings with poor sanitation. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains have significantly complicated treatment, especially in vulnerable pediatric populations. This study aimed to characterize the genetic profiles of drug resistance in MDR and XDR S. typhi isolates from pediatric patients. Methods: A cross-sectional study was conducted on 800 blood samples from pediatric typhoid patients. S. typhi isolates were identified using the BacT/ALERT 3D system, followed by culture on MacConkey and blood agar. Antimicrobial susceptibility was assessed using the disk diffusion method according to CLSI 2022 guidelines. Whole-genome sequencing (WGS) was performed on 29 isolates using Illumina MiSeq technology, and resistance genes and mutations were analyzed. Results: Antimicrobial susceptibility testing revealed that 68 (48.57%) of S. typhi isolates were XDR and 61 (43.57%) were MDR, exhibiting widespread resistance to ciprofloxacin, ampicillin, chloramphenicol, ceftriaxone, and co-trimoxazole. WGS identified key resistance genes across all 29 isolates, including bla_CTX-M-15, bla_TEM-1B, qnrS1, aac(6′)-Iaa, catA1, dfraA7, sul1, qacEΔ1, and the gyrA-S83F mutation. Notably, gyrA-S83F and qnrS1 were detected in all isolates and strongly correlated with ciprofloxacin resistance. Virulence genes were consistently present in all isolates, indicating a high pathogenic potential. The IncY plasmid, found in four (14%) isolates, was linked to resistance against third-generation cephalosporins, including ceftriaxone. Conclusion: This study underscores the alarming prevalence of MDR and XDR S. typhi isolates among pediatric patients, driven by resistance genes such as bla_CTX-M-15, bla_TEM-1B, and gyrA-S83F. These findings highlight the urgent need for targeted therapeutic strategies and robust surveillance systems to combat the growing threat of drug-resistant typhoid fever. Full article

Historical chemical production sites often harbor irregularly distributed solid waste landfills, posing significant environmental risks. Traditional drilling methods, while accurate, are inefficient for comprehensive characterization due to high costs and spatial limitations. This study aims to develop an integrated geophysical drilling approach to accurately delineate the spatial distribution and volume of landfilled solid waste (predominantly organic pollutants) at two decommissioned chemical plant sites (total area: 8954 m²). Methods: We combined (1) geophysical surveys (transient electromagnetic (TEM, 50 profiles, 2936 points), high-density resistivity (HDR, 2 profiles, 192 points), and ground-penetrating radar (GPR, 22 profiles, 1072.1 m)) and (2) systematic drilling verification (136 boreholes, ≤10 m × 10 m density). Anomalies were interpreted through integrating geophysical responses, historical records, and borehole validation. Spatial modeling was conducted using Kriging interpolation in EVS software. The results show that (1) the anomalies exhibited a “sparse multi-point distribution” across zones A2 (primary waste concentration), A4, and A6, which were differentiated into solid waste, foundations, contaminated soil, voids, and cracks; (2) drilling confirmed solid waste at nine locations (A2: “multi-point, small-quantity” residues; A6: contaminated clay layers with garbage) with irregular thicknesses (0.2–1.3 m); (3) TEM identified diagnostic medium–high-resistivity anomalies (e.g., 28–37 m in A4L3), while GPR detected 17 shallow anomalies (only one validated as waste); and (4) the total waste volume was quantified as 266.9 m³. The methodology reduced the field effort by ∼35% versus drilling-only approaches, resolved geophysical limitations (e.g., HDR’s volume effect overestimating the thickness), and provided a validated framework for efficient characterization of complex historical landfills. Full article

A solar-pumped Ce:Nd:YAG laser amplifier design is proposed to address the challenge of scaling output power in solar-pumped laser oscillators while maintaining high beam quality. The design employs a 1.33 m² flat Fresnel lens with a 2 m focal length as a primary concentrator, which is combined with a secondary homogenizing concentrator, featuring 40 mm × 40 mm input aperture, 200 mm length, and 11.3 mm × 26 mm output aperture, to provide efficient coupling and uniform distribution of solar radiation onto a 2.9 mm thick Ce:Nd:YAG slab with 11.3 mm × 26 mm surface area and two beveled corners. This geometry enables multiple total internal reflections of a 1064 nm TEM₀₀ mode seed laser beam inside the slab, ensuring efficient interaction with the active Ce³⁺ and Nd³⁺ ions in the gain medium. Performed numerical analysis shows that the present approach can deliver a uniform solar pump power density of 2.5 W/mm² to the slab amplifier. This value is 2.05-times higher than the numerically calculated power density incident on the Nd:YAG slab of the previous solar-pumped amplifier that achieved the highest continuous-wave laser gain of 1.64. Furthermore, the optimized slab geometry with 0.44 width-to-height ratio allows the seed laser to undergo 32 internal reflections, extending its optical path length by a factor of 1.45 compared to the earlier design. These numerical achievements, combined with the Ce:Nd:YAG medium’s capacity to deliver nearly 1.57-times more laser power than Nd:YAG, reveal the potential of proposed design to yield a gain enhancement factor of 4.16, making the first solar-pumped Ce:Nd:YAG amplifier a promising solution toward energy-efficient, sustainable solutions for terrestrial and space applications. Full article