Search Results (1,070)

This article focuses on the research and development of innovative polymer-concrete composites for the manufacture of precision machine tool frames and critical mechanical engineering components. The relevance of this work stems from the need to replace traditional cast iron and cement concrete with materials with superior damping properties and thermal stability. The polymer matrix used in this study was ED-20 epoxy-diane resin, modified with (FAM) furan resin and cured with polyethylenepolyamine (PEPA), which together ensured minimal linear shrinkage (less than 0.5–1%) during polymerization. The focus was on the effect of multimodal filler distribution, including quartz sand, gabbro, and basalt, as well as reinforcing additives such as silicon carbide and fiberglass, on the final performance characteristics of the material. Experimental studies determined the key physical and mechanical parameters of the obtained samples. The results showed that the optimized composition (Smp_001) exhibited compressive strength up to 92.3 MPa, significantly exceeding that of standard high-strength concrete. It was established that the use of silicon carbide and glass fiber promotes the formation of a dense heterogeneous microstructure characterized by extremely low porosity (1.2–2.5%) and record-low water absorption (less than 0.05%). These characteristics guarantee high dimensional stability of the frames during prolonged contact with process fluids and cutting fluids. The scanning electron microscopy (SEM) and (EDS) energy dispersive X-ray spectroscopy methods confirmed the dense packing and high degree of interaction of the polymer matrix with the crystalline phases of the filler. This condition of the interfacial boundaries guarantees stable stress transfer throughout the entire volume of the material, which minimizes the risk of local damage during operation. The study confirmed that the developed material has vibration damping properties 6–10 times more effective than gray cast iron, a critical factor in improving machining accuracy on modern metal-cutting machines. The scientific novelty of the study lies in its substantiation of the synergistic effect of the combined use of basalt fillers and silicon carbide to achieve the precision properties of a structural material. Its practical significance is confirmed by the possibility of producing large-scale parts by casting without the need for complex finishing, opening up new prospects for modernizing the machine tool industry. Full article

The article presents the synthesis and characterization of double halide perovskites (DHPs) with the nominal composition Cs₂Ag_0.2Na_0.4In_0.6M_0.4Cl₆ (M = Si, Ti, Zr), including photoluminescence (PL), photoluminescence excitation (PLE) spectra measured over a range of temperatures and kinetics of luminescence. The materials were synthesized via a hydrothermal method. The phase purity and elemental composition of the synthesized perovskites were confirmed by X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and elemental analysis, which demonstrated that the samples showed a close match to the target stoichiometry. The PL spectra exhibit a systematic shift toward the lower-energy region with substitution from Si to Zr, correlating with the progressive increase in the ionic radii of the substituting cations. All samples display broad, asymmetric emission bands, characteristic of self-trapped excitonic (STE) states. Temperature-dependent PL measurements reveal a gradual decrease in emission intensity with increasing temperature for all samples. The maximum emission intensity is observed in the range of ~160–200 K, corresponding to optimal conditions for radiative recombination, whereas the lowest intensity is recorded at ~80–100 K, where thermal activation of radiative centers is minimal. An increase in temperature is accompanied by a red shift in the PL bands across all compositions. In the Ti-doped DHP, a pronounced blue shift at low temperatures is observed, which can be attributed to the involvement of Ti³⁺-related electronic states. An analysis of the activation energy of thermal luminescence quenching and the results of time-resolved spectroscopy revealed the activation of thermal processes in the titanium-containing sample and their rapid decay, whereas replacing titanium with silicon leads to more stable luminescence in the crystal under study. Thus, the enhanced luminescence characteristics of double halide perovskites doped with Ti, Si, and Zr highlight their potential for advanced photonic and optoelectronic applications. Full article

Rare earth element (REE) detection sensitivity with minimal sample damage is exciting. Laser-induced breakdown spectroscopy (LIBS) with a typical methodology is a useful diagnostic tool, but often shows poor REE sensitivity. This study presents the qualitative, quantitative, and classification analysis of REE-bearing ore samples that contain multiple elements from the lanthanoid (Ln) group (e.g., La, Ce, Nd, Sm, and Gd) using the LIBS technique, and the results are compared with those obtained using a magnetic-field-assisted LIBS (MFA-LIBS) system. The LIBS spectrum was recorded using a Nd:YAG Laser with a 532 nm emission wavelength, a 5 ns pulse duration, and a 10 Hz repetition rate. Optical regions exhibiting the strongest emission lines of REEs were identified, followed by MFA-LIBS to improve the qualitative signatures of the elements of interest. MFA-LIBS also assists in confirming signal enhancement for Sm and Gd, which were unidentified with a conventional LIBS setup. Quantitative analysis was performed using a calibration-free and magnetic-field-assisted LIBS (CF-MF-LIBS) method. La, Ce, and Nd concentrations were estimated to be from 1 to 3 wt.%, whereas Sm and Gd were detected within 0.5 wt.%. The results obtained using CF-MF-LIBS were compared with those obtained using the X-ray fluorescence spectroscopy (XRF) technique, showing good agreement between the LIBS/XRF techniques. Further, the limit of detection (LOD) of the REEs using in-house prepared samples was estimated, and the results were compared with those previously reported in the literature. Furthermore, classification analysis of REE ores based on compositional variations was achieved using principal component analysis (PCA). The first two principal components (PCs) with maximum spectral variance, such as PC1~74.5% and PC2~14.5%, were considered for the clustering, and ellipses with 95% confidence using major (x) and minor (y) axes were created to explore outliers. Therefore, the CF-MF-LIBS method in combination with PCA demonstrates a rapid, robust, and effective methodology for the detection, quantification, and classification investigation of REE-bearing ores. Full article

The ionosphere is the ionized region of the atmosphere, extending roughly from 60 km to 1000 km in altitude. During flares, the near-Earth space is subjected to high-energy X-ray and EUV (extreme ultraviolet radiation) radiation, which also impacts the ionosphere. The changes in the ionospheric parameters measured by ionosondes, namely the f_min (minimum frequency) and foF2 (F2-layer ordinary-mode critical frequency) values, were examined during solar flares that occurred in geomagnetically quiet conditions (Dst (Disturbance Storm Time index) > −40 nT, Kp (planetary K-index) < 4). The necessary data were obtained by manually evaluating ionograms recorded by the Czech DPS4D ionosonde at Pruhonice (PQ052). The degree of variation was compared to quiet reference days, allowing for the determination of the deviations in the required values (df_min, dfoF2). The time series of the deviations were investigated. Furthermore, the relationship between the deviations and a “geoeffectiveness” parameter of the solar flare was also examined. The X-ray flux, the solar zenith angle of the station at the time of the event, and the position of the flare on the solar disk were also taken into account for the determination of the “geoeffectiveness” parameter. A positive correlation was observed between df_min and the geoeffectiveness parameter of the flare, which was more significant than the correlation between the dfoF2 and the geoeffectiveness parameter. Full article

Background: Pulmonary arterial hypertension is a rare but life-threatening condition in children, with hereditary forms often being linked to mutations in genes such as bone morphogenetic protein receptor type 2 (BMPR2), caveolin 1 (CAV1), and potassium channel subfamily K member 3 (KCNK3). Among these, CAV1 mutations are associated with severe disease phenotypes, though cases resulting from de novo heterozygous CAV1 mutations with multi-system involvement remain rarely reported. The CAV1 mutation (c.424C > T, p.Q142X) disrupts caveolin-1 function, leading to dysregulated pulmonary vascular remodeling and multi-system abnormalities. Methods: This was a retrospective case study of a pediatric patient with hereditary PAH. The patient was followed at our hospital from initial presentation until death. Clinical data were collected from medical records, including physical examinations, laboratory tests, echocardiography, chest X-ray, computed tomography pulmonary angiography (CTPA), and genetic analysis. The patient was treated sequentially with various PAH-targeted medications. This report also includes a review of the relevant literature on CAV1-associated PAH. Results: A female aged 3 years and 11 months was diagnosed with hereditary PAH associated with a de novo heterozygous CAV1 mutation (c.424C > T, p.Q142X). Both parents underwent genetic testing and were negative for the mutation, confirming its de novo origin. Clinical manifestations included special facial features, congenital telangiectasia, cutis marmorata (marbled skin), congenital cataract, hereditary lipodystrophy, and severe PAH. The patient presented with progressive exercise intolerance, syncope, and worsening dyspnea over nine years. Echocardiography revealed pulmonary hypertension with an estimated pulmonary artery systolic pressure of 69–105 mmHg, right heart enlargement, right ventricular hypertrophy, and moderate tricuspid regurgitation. Blood and urine metabolic screenings were normal. A chest X-ray showed progressive enlargement of the cardiac silhouette and bulging of the pulmonary artery segment. CTPA demonstrated pulmonary hypertension, secondary right heart dysfunction, decompensated right ventricular function, and mosaic perfusion in both lungs, suggestive of small arterial branch occlusion. Right heart catheterization was declined by the parents. Thus, the diagnosis of PAH was established based on clinical, echocardiographic, CTPA, and genetic findings. The patient was hospitalized four times and lost to follow-up from 2017 to 2023. She received sequential treatment with digoxin, hydrochlorothiazide, tadalafil, ambrisentan, selexipag, and treprostinil. Despite these therapies, pulmonary artery pressure continued to rise with progressive clinical deterioration. The patient ultimately died at 13 years of age due to a pulmonary hypertensive crisis and multiple organ failure following a severe episode of gastroenteritis. Conclusions: Despite aggressive treatment with multiple targeted reduced pulmonary artery pressure drug therapies, managing hereditary PAH caused by CAV1 mutations in children remains a significant challenge, with a high mortality rate. Early genetic diagnosis, regular follow-up, and individualized treatment are crucial. It requires the joint efforts of patients, parents, and healthcare providers. Full article

Background/Obejctives: Sarcopenic obesity (SO) has gained growing attention in metabolic dysfunction-associated steatotic liver disease (MASLD), yet data in Caucasian populations remain limited. The aim of this study was to assess the prevalence of SO using different definitions and to explore its relationship with steroid androgens, physical performance and frailty in MASLD individuals. Methods: Two hundred Caucasian patients with MASLD and available dual-energy X-ray absorptiometry (DEXA) data were evaluated. Clinical, biochemical, hormonal and elastography data were recorded, while physical performance was assessed using the Short Physical Performance Battery (SPPB) and Liver Frailty Index (LFI). Results: SO prevalence ranged from 34.5% to 76.5% depending on the definition applied (AIMSO score, body mass index, and body fat percentage-based criteria). Across definitions, SO individuals showed greater hepatic steatosis, more metabolic comorbidities and demonstrated poorer physical performance. Lower dehydroepiandrosterone sulfate (DHEAS) levels were independently associated with SO when the definition is based on total body fat percentage, and waist circumference (WC) was consistently linked to SO across all definitions. Separate analysis based on gender, confirmed that DHEAS was independently associated with SO in men, while WC represented an independent factor associated with SO in both genders. Conclusions: In conclusion, SO is common among Caucasian MASLD patients and is accompanied by metabolic, hepatic, hormonal, and functional alterations. These findings may help recognize patients at risk of SO and support more focused assessment and monitoring in clinical practice. Full article

Background/Objectives: Regional adipose tissue has been studied as a prognostic factor in various extra-hepatic diseases, but data in the setting of cirrhosis is scarce. Our aim was to evaluate the association of regional adipose tissue indices with the severity of liver disease and its impact on the outcome of patients with cirrhosis. Methods: Three hundred and thirty-seven patients with cirrhosis were prospectively enrolled in the study. Clinical and laboratory data were recorded, and MELD-Na and Child-Turcotte-Pugh scores were calculated. Physical performance was evaluated with handgrip strength, the Short Physical Performance Battery test, and the Liver Frailty Index. Dual-energy X-ray absorptiometry was used for the evaluation of total and regional lean and fat mass. Results: A low trunk fat percentage was found to be independently associated with a MELD-Na score ≥ 15 (Odds Ratio: 0.92, p = 0.007). MELD-Na score and trunk fat percentage were the only factors independently associated with mortality [Hazard Ratio (HR): 1.078, p = 0.02 and HR: 0.95, p = 0.03, respectively], while a separate analysis based on gender confirmed this finding only in men. In the total cohort, patients with a trunk fat percentage < 27.5% had worse outcomes (log-rank 11.4; p < 0.001). Conclusions: This study marks the first effort to examine the association of indices related to regional adipose tissue distribution with the severity of liver disease and outcome. Trunk fat percentage was the only body composition parameter independently associated with advanced liver disease and prognosis in the total cohort specifically in men, but not in women. Further studies are needed to validate the predictive role of adipose tissue in patients with cirrhosis. Full article

Three types of graphene–single crystal titanium dioxide composite (GR–TiO₂SCs) were prepared using the hydrothermal method, employing TiF₄ and graphite as raw materials with hydrofluoric acid serving as the morphology-directing agent. The phase composition and morphological features of the resultant composites were systematically characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction. These complementary characterization results clearly demonstrate that graphene and TiO₂ single crystals have been successfully hybridized to form a well-defined heterostructure, rather than a simple physical mixture. Photocatalytic performances were evaluated by monitoring the photodegradation behaviors of methylene blue, rhodamine B, and methyl orange solutions under simulated light irradiation, with real-time concentration variations recorded by UV–visible absorption spectroscopy. The composite sample in which TiO₂SCs were in situ grown and uniformly anchored onto graphene oxide substrates effectively suppressed the self-stacking and agglomeration of individual crystallites, thus delivering the best photocatalytic response. Increased exposure of the active catalytic interfaces of TiO₂SCs was found to play a key role in elevating the overall photocatalytic activity. The hierarchical assembly protocol developed in this work provides a feasible pathway for the rational design of functional composites with controllable microstructures and tailored properties, which can be further extended to the development of advanced sensing materials. Full article

The Lower Permian Fengcheng Formation (P₁f) in the Mahu Sag, Junggar Basin, records an uncommon alkaline–lacustrine hybrid system where siliciclastic, volcaniclastic inputs, and endogenous carbonates jointly build strong reservoir heterogeneity. This study clarifies how depositional framework architecture and diagenetic evolution jointly control effective pore–throat connectivity and reservoir effectiveness. We examined 55 core samples from nine wells using X-ray diffraction (XRD), scanning electron microscopy (SEM), low-pressure N₂ adsorption (LPNA), high-pressure mercury intrusion (HPMI), and nuclear magnetic resonance (NMR) T₂ spectra, and identified five lithofacies: siliciclastic-dominated (SDF), volcaniclastic (VTF), mixed siliciclastic–carbonate (MSCF), carbonate-dominated (CDF), and alkaline mineral-rich (AMF). Reservoir quality is strongly lithofacies-dependent and cannot be inferred from pore volume alone. The SDF and CDF are both dominated by the >200 nm domain, but only the SDF preserves a coarse pore–throat framework that sustains effective flow; the MSCF is characterized by a stronger 10–50 nm contribution and a more tortuous network, and the VTF by enrichment of the 50–200 nm domain. In the SDF, quartz is preferentially associated with the >200 nm domain and dolomite with the 50–200 nm domain, consistent with coarse residual pores preserved by rigid grains and intercrystalline or dissolution-related pores, respectively. The AMF should be treated as two subtypes: the Na-borosilicate subtype shows high >200 nm volume but very high tortuosity, whereas the Na-carbonate subtype shows co-development of the 10–50 nm and >200 nm domains with lower threshold pressure and tortuosity, indicating better pore-body–throat matching and more favorable reservoir behavior. These findings provide a lithofacies-based framework for screening effective reservoir intervals in alkaline lacustrine hybrid systems. Full article

Tree rings record environmental conditions and can serve as long-term biomonitors of urban pollution. This study evaluated the radial growth and chemical composition of Pinus greggii wood in three urban green areas of Mexico City: San Juan de Aragón Park (SJA), Sierra de Guadalupe State Park (GUAD), and Vivero Coyoacán National Park (COY). Tree ring chemical elements were analyzed at annual resolution for the period 2002 to 2022, and their relationships with atmospheric pollutant concentrations, including nitrogen oxides (NO_x), carbon monoxide (CO), ozone (O₃), and particulate matter (PM), of medium size or smaller than 10 µm, including the fractions PM_2.5 and PM₁₀, were assessed using a spatial scaling approach. Elemental concentrations were determined using X-ray fluorescence (XRF). Statistical analyses included analysis of variance (ANOVA), Theil–Sen trend estimation, and Pearson correlation with lag analysis (up to 3 years). The oldest trees were recorded in COY (52 years), while the youngest were recorded in GUAD (13 years). Distinct temporal patterns in elemental concentrations were detected among sites; for instance, peak concentrations of Fe (307 ppm), Cu (11 ppm), and Zn (51 ppm) occurred in GUAD in 2021, while Pb concentrations declined during 2019–2020 across all three sites. Significant correlations (p < 0.05) were identified between Cu, Fe, Zn, and Pb and the atmospheric pollutants (NO_x, PM_2.5, PM₁₀, O₃). Notably, O₃ showed significant positive correlations with Fe at SJA (up to r = 0.80) and GUAD (up to r = 0.46) with lags ranging from 0 to 3 years, suggesting delayed responses between atmospheric pollution and elemental deposition in tree rings. These findings highlight the sensitivity of P. greggii to urban atmospheric pollution and support its potential as a long-term biomonitoring tool, as well as its importance for informing policies aimed at improving air quality and promoting the sustainable management of urban green spaces. Full article

Background: Three-dimensional (3D) mapping of the left atrium (LA) using multipolar high-density (HD) catheters plays a central role in contemporary LA ablation procedures, as accurate and efficient acquisition of anatomical and electrophysiological information is essential. This study benchmarks workflow efficiency during acquisition of a predefined complete HD LA map across four widely used multipolar HD catheter designs. The analysis focuses on efficiency metrics and does not aim to assess mapping quality, arrhythmia interpretation accuracy, or clinical outcomes. Methods: We analyzed 182 consecutive patients from an ongoing cohort undergoing LA procedures, including pulmonary vein isolation and complex LA ablations, using 3D mapping in accordance with current guideline recommendations. Four multipolar HD catheters were applied according to the respective 3D mapping systems: a basket catheter (Orion, Rhythmia), a grid catheter (HD Grid, EnSite X), a penta-spline catheter (PentaRay, Carto 3), and an octa-spline catheter (OctaRay, Carto 3). For each procedure, the time required for acquisition of a complete 3D LA map and the number of acquired points were systematically recorded. LA HD mapping speed was calculated by relating LA volume to the time required for complete map acquisition. Results: The study population had a mean age of 69 years, with a median CHA₂DS₂-VASc score of 3, indicating a cohort with a moderate thromboembolic risk profile. The median LA volume index (LAVI) was 34 mL/m². Patients were distributed across four HD catheter groups, comprising 44 patients in the basket group, 29 in the grid group, 23 in the penta-spline group, and 86 in the octa-spline group. LA mapping speed differed significantly among the groups, with values of 3 mL/min in the basket group, 2.5 mL/min in the grid group, 3.1 mL/min in the penta-spline group, and the highest mapping speed observed in the octa-spline group at 5.9 mL/min. Conclusions: The octa-spline catheter was associated with a significantly higher LA mapping speed compared with other widely used HD catheters. Full article

Nephrite is a significant jade resource, and systematic investigation of its deposits contributes to regional metallogenic synthesis and exploration targeting. The recently discovered white nephrite deposit in the Dikou area, Fujian Province, remains inadequately characterized. This study presents a comprehensive mineralogical investigation employing polarizing microscopy, scanning electron microscopy, electron probe microanalysis, X-ray powder diffraction and laser Raman spectroscopy to elucidate the mineralogical and petrochemical characteristics of Dikou nephrite and constrain its genesis. The results demonstrate that tremolite constitutes the predominant mineral phase, accompanied by abundant diopside and quartz, with minor dolomite, prehnite, and apatite. Based on subtle compositional variations, tremolite can be categorized into two generations: early metasomatic Tr-I and late-stage Tr-II. All tremolite samples exhibit Fe-depleted, Mg-enriched composition with Mg# > 0.99. The mineral assemblage and textural relationships record multiple episodes of hydrothermal metasomatism. Integrated with the regional geological constraints, the deposit formation is genetically linked to the Neoproterozoic–Early Paleozoic ocean–continent transition of the South China Plate and is classified as D-type nephrite. The Dikou nephrite exhibits the mineral assemblage typical of dolomite-related deposits, displaying a distinctive felt-like fibrous texture that yields a homogeneous structure and superior aesthetic quality. Its Fe-depleted composition imparts a notably lighter coloration relative to D-type nephrite from other deposits. This study advances understanding of Dikou nephrite genesis, highlights the diversity of metallogenic environments in Fujian Province, and provides a theoretical framework for exploration of analogous deposits. Full article

Background/Objectives: Accurate quantification of alveolar cleft defects for bone grafting remains difficult due to inconsistent anatomical boundaries. This study established an expert consensus on boundary landmarks for alveolar bone graft (ABG) planning and validated the accuracy and reliability of digital volumetric measurement methods. Methods: Three cleft specialists performed repeated simulated graft procedures in seven patient-specific 3D-printed models, first according to the operator’s clinical judgment, and subsequently according to panel-derived consensus boundaries. Two radiologists independently conducted digital volumetric assessments in 3D X-ray imaging using four measurement approaches (axial tracing, interpolated axial tracing, landmark-based mirroring, and mesh-based mirroring), generating 56 independent digital segmentations to be evaluated against the consensus-based physical reference standard. Volumes of the defects were recorded, intra- and inter-rater reliabilities were calculated using the intraclass correlation coefficient (ICC), and differences among methods were analyzed. Results: Operator-defined plans showed significant inter-operator differences (p < 0.001) with poor-to-excellent reliability (intra-rater ICC 0.060–0.967; inter-rater ICC 0.300–0.635). Consensus established standardized boundaries: tilted plane from base of anterior nasal spine to hard palate, cemento-enamel junctions, incisive canal, and alveolar contour. Consensus-based filling showed non-significant inter-rater differences (p = 0.139) and substantially improved reliability (intra-rater ICC 0.904–0.988; inter-rater ICC 0.622–0.861). Among the four digital methods evaluated, axial tracing demonstrated excellent reliability (intra-rater ICC 0.971–0.99; inter-rater ICC 0.965) and high accuracy (mean difference 0.001–0.026 cm³), with no significant difference (p = 0.999) from the physical reference standard. Conclusions: These proposed consensus-based boundary definitions and validated volumetric measurement methods improved the accuracy and reproducibility of personalized alveolar bone graft planning. Full article

Background: Osteocalcin is a bone-derived protein traditionally regarded as a marker of bone formation, but experimental and clinical studies have suggested potential endocrine effects on energy and glucose metabolism. In pediatric populations, particularly in the context of obesity, the relationships between circulating osteocalcin, adiposity, and metabolic health remain inconsistent and poorly defined. Objective: To investigate associations between serum total osteocalcin and anthropometric, metabolic, biochemical, and body composition parameters in children and adolescents with obesity, with particular emphasis on adiposity and mineral metabolism. Methods: This retrospective cross-sectional study included 155 children and adolescents aged 4–18 years with obesity. Anthropometric measurements, laboratory parameters, and body composition assessed by dual-energy X-ray absorptiometry were extracted from medical records. Associations between osteocalcin z-scores and clinical variables were evaluated using linear regression models. Multivariable and extended regression models were applied to assess independent associations. Results: Osteocalcin was positively associated with markers of mineral metabolism, including serum 25-hydroxyvitamin D₃ (β = 0.19, p = 0.012), serum calcium (β = 0.19, p = 0.015), and free triiodothyronine (β = 0.32, p < 0.001) in multivariable analyses. No independent associations were observed between osteocalcin and measures of adiposity, including body mass index, visceral adipose tissue index, leptin, or markers of glucose and lipid metabolism. Conclusions: In children and adolescents with obesity, circulating osteocalcin is primarily associated with mineral metabolism rather than adiposity or metabolic health. These findings support the interpretation of total osteocalcin as a clinically accessible marker of bone turnover and mineral homeostasis rather than a robust surrogate of metabolic dysfunction in pediatric obesity. Full article

Two-dimensional (2D) materials exhibit electronic and collective excitation properties that are highly sensitive to surface chemistry and thickness, requiring surface-sensitive characterization at low electron energies. Here, we investigate graphene, hexagonal boron nitride (h-BN), molybdenum disulfide (MoS₂), and titanium carbide (Ti₃C₂) MXene using an advanced home-built scanning low-energy electron microscopy system combined with time-of-flight electron spectroscopy (SLEEM/ToF). The system uniquely records electron energy-loss spectra (EELS) from transmitted electrons rather than from the reflected electrons used in conventional SLEEM. Compared with high-energy EELS, our low-energy ToF-EELS approach offers enhanced surface sensitivity and reduced beam-induced damage, enabling direct probing of π and π + σ plasmon excitations. Additionally, complementary techniques, including scanning transmission electron microscopy (STEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), were employed to characterize structural and chemical properties. EELS were acquired for all investigated 2D materials at electron landing energies of 500–1500 eV, and in the 5–50 eV range for selected materials, including graphene and MoS₂. Analysis of these spectra enabled determination of the average plasmon positions across the measured energy range for all studied materials. Furthermore, a quantitative determination of the inelastic mean free path (IMFP) was achieved for graphene in the 10–50 eV range, yielding a value of 1.9 ± 0.2 nm. These results demonstrate the potential of SLEEM–ToF for surface-sensitive analysis of 2D materials. Full article