Search Results (1,330)

An equiatomic Ni-Fe alloy was synthesized through mechanosynthesis, under an argon atmosphere using a planetary ball mill, after 100 h. To assess the phase stability, the alloy was subsequently annealed at 923.15 K for 2 h. At the end of mechanosynthesis, X-ray diffraction analysis revealed the formation of two distinct solid phases, FCC γ-NiFe (wt% = 90.3%) and BCC α-FeNi (wt% = 9.7%). The lattice parameter of the FCC phase stabilized at 3.5748 Å, whereas the BCC phase exhibited a lattice parameter of 2.6608 Å. The average crystallite size was determined to be around 7 nm with the lattice strains quantified as 0.48% for both phases. This significant refinement of microstructure indicates extensive plastic deformation within the grains. Scanning electron microscopy revealed an angular particle morphology with an average particle size of 8.15 µm. Differential scanning calorimetry (DSC) analysis identified an exothermic transition at 623.15 K, corresponding to the Curie temperature of nickel, and another one at 873.15 K, attributed to the Curie temperature of Ni₃Fe. These results demonstrate the efficiency of mechanosynthesis in producing biphasic Ni-Fe nanomaterials with tailored properties, characterized by a dominant FCC phase with a highly deformed nanocrystalline structure. These findings highlight the great influence of mechanical milling on the structural properties of the Ni-Fe alloy in terms of a high density of stored crystalline defects. Full article

Lattice structures offer unique mechanical properties and versatility in engineering applications, yet existing designs often struggle to balance performance and material efficiency. This study introduces the brachistochrone curve as a novel framework for optimizing lattice geometries, enhancing mechanical behavior while minimizing material usage. Using finite element simulations and compressive testing of 3D-printed samples, we analyzed the mechanical response of brachistochrone-based (B-) and standard lattice structures (diamond, IWP, gyroid, and BCC). We investigated the scaling behavior of the volume-to-surface area ratio, incorporated fractal dimension analysis, and compared experimental and numerical results to evaluate the performance of B-lattices versus standard designs (S-). Our findings indicate that brachistochrone-inspired lattices enhance mechanical efficiency, enabling the design of lightweight, high-strength components with sustainable material use. Experimental results suggest that B-gyroid lattices exhibit lower stiffness than S-gyroid lattices under small displacements, highlighting their potential for energy absorption applications. Full article

Additive manufacturing has revolutionized the production industry by enabling the fabrication of complex geometries. In recent years, significant advancements have been made in 3D printing using metal filament, particularly with materials such as 316L stainless steel. Known for its high strength, corrosion resistance, and ductility, 316L stainless steel is well suited for demanding applications in the medical, marine, and aerospace industries. However, secondary processes such as debinding and sintering can lead to changes in the dimensions and mechanical properties of the final product. This study investigates the effect of layer thickness on the mechanical properties of 316L stainless steel produced through additive manufacturing. Samples were produced with varying layer thicknesses (100, 200, 300, and 400 µm) and tested for tensile strength, hardness, and density. The results indicate that tensile strength increases with decreasing layer thickness. The highest tensile strength (432 MPa) and hardness (213 Hv) were observed at a layer thickness of 100 µm. Additionally, phase analyses and microstructural examinations were conducted. The primary phases identified in the samples were face-centered cubic (FCC) austenite and body-centered cubic (BCC) ferrite (δ). In this study, the manufacturing parameters with 316L filament have been optimized, and their impact on the mechanical properties has been examined. Full article

The interaction between the high-entropy alloy CoCrCu₂FeNi and diamond, as well as the graphitization of diamond, were investigated using in situ transmission electron microscopy in the temperature range of 20–900 °C. To ensure the absence of interaction between diamond and the HEA at the initial stage of the experiment, the test sample was prepared by magnetron sputtering of the CoCrCu₂FeNi coating on a diamond single crystal. The following stages of the interaction of diamond with the CoCrCu₂FeNi alloy were discovered. A partial transformation of FCC to BCC crystal lattice occurs in CoCrCu₂FeNi HEA at 500 °C. At a temperature of 700 °C, the process of diffusion of Fe, Co, Ni, and Cu over the diamond surface commences. These elements catalyze the transformation of diamond into graphite at a temperature of 800 °C. Carbon in graphite interacts with chromium from the HEA to form Cr₇C₃ carbide. At 900 °C, a secondary copper-based phase with an FCC lattice is formed within the CoCrCu₂FeNi coating. Full article

Background/Objectives: Basal cell carcinoma (BCC) is the most common malignancy, characterised by local invasiveness and the potential for tissue destruction. Diagnosing BCC can be challenging, particularly for less experienced dermatologists. Line-field confocal optical coherence tomography (LC-OCT), a new noninvasive optical technique, has become increasingly useful in clinical practice, allowing in vivo imaging at cellular resolution. This study aimed to evaluate the impact of a 1 h structured training session on the ability of dermatology residents to diagnose BCC using LC-OCT. Methods: Eight dermatology residents with different levels of LC-OCT experience (no experienced and low experience in LC-OCT) participated alongside an expert dermatologist as a benchmark. Overall, participants evaluated 40 histopathologically confirmed lesions (20 BCC, 20 non-BCC) before and after training, with and without the inclusion of dermoscopic images. Results: We observed a significant improvement in diagnostic accuracy post-training, especially among inexperienced users, with a 20% reduction in false negatives and a 35% reduction in false positives. When the dermoscopic images were included, further improvements were noted, with the accuracy increasing by an additional 5%. The overall diagnostic rate for inexperienced readers increased from 48% to 76% after training and to 81% with the addition of dermoscopic images in the course. Conclusions: Our study highlights the effectiveness of short, targeted training in enhancing the diagnostic utility of LC-OCT, emphasising its potential for broader clinical adoption to improve BCC detection. Full article

Refractory high-entropy or medium-entropy alloys (RHEAs, RMEAs) exhibit outstanding strength and hold significant promise for high-temperature applications. However, their pronounced brittleness at room temperature restricts their industrial application. Recently, the introduction of interstitial oxygen has proven effective in refining the microstructure and improving the mechanical properties of RMEAs. In this study, we investigated the effect of interstitial oxygen content ranging from 0.5 to 6 at.% on the microstructures and mechanical properties of TiZrNb MEA. The alloys display a single BCC structure, showing a dendritic crystal morphology. At an oxygen content of 4 at.%, the alloy shows a room-temperature compressive yield strength of 1300 MPa and compressive strain of over 50%, achieving a balanced strength and ductility combination. Moreover, it shows excellent high-temperature mechanical properties, with yield strength exceeding 500 MPa at 800 °C. The Toda-Caraballo and Labusch theoretical models were used in the study to clarify the strengthening mechanism of the alloys, and the theoretical yield strengths obtained by calculation coincided with the experimental yield strengths. This validation not only confirms that the primary strengthening mechanism is solid solution strengthening, but also proves the reliability of the model in predicting the mechanical properties of MEAs and provides a theoretical basis for the use of interstitial atoms to strengthen MEAs. Full article

Understanding the mechanical behavior of materials under various strain-rate regimes is critical for many scientific and engineering applications. Accordingly, this study investigates the strain-rate-dependent compressive mechanical behavior of B2-containing (TiZrNb)_79.5(TaAl)_20.5 refractory high-entropy alloy (RHEA) at room temperature. The RHEA is prepared by vacuum arc melting and is tested over intermediate (1.0 × 10⁻¹ s⁻¹, 1.0 s⁻¹) and dynamic (1.0 × 10³ s⁻¹, 2.0 × 10³ s⁻¹, 2.8 × 10³ s⁻¹, 3.2 × 10³ s⁻¹, and 3.5 × 10³ s⁻¹) strain rates. The alloy characterized as hybrid body-centered-cubic (BCC)/B2 nanostructure reveals an exceptional yield strength (YS) of ~1437 MPa and a fracture strain exceeding 90% at an intermediate (1.0 s⁻¹) strain rate. The YS increases to ~1797 MPa under dynamic strain-rate (3.2 × 10³ s⁻¹) loadings, which is a ~25 % improvement in strength compared with the deformation at the intermediate strain rate. Microstructural analysis of the deformed specimens reveals the severity of dislocation activity with strain and strain rate that evolves from fine dislocation bands to the formation of localized adiabatic shear bands (ASBs) at the strain rate 3.5 × 10³ s⁻¹. Consequently, the RHEA fracture features mixed ductile–brittle morphology. Overall, the RHEA exhibits excellent strength–ductility synergy over a wide strain-rate domain. The study enhances understanding of the strain-rate-dependent mechanical behavior of B2-containing RHEA, which is significant for alloy processes and impact resistance applications. Full article

The excellent mechanical properties of high-entropy alloys, especially under harsh service environments, have attracted increasing attention in the last decade. FCC-based and refractory high-entropy alloys (HEAs) are the most extensively used series. However, the strength of FCC-base HEAs is insufficient, although they possess a great ductility and fracture toughness at both room and low temperatures. With regard to the BCC-based refractory HEAs, the unsatisfactory ductility at room temperature shadows their ultrahigh strength at room and high temperatures, as well as their excellent thermal stability. In order to strike a balance between strength and toughness, strengthening mechanisms should be first clarified. Therefore, typical mechanical performance and corresponding strengthening factors are systemically summarized, including the solid solution strengthening, second phase, interface, and synergistic effects for FCC-base HEAs, along with the optimization of principal elements, construction of multi-phase, the doping of non-metallic interstitial elements, and the introduction of kink bands for refractory HEAs. Among which the design of meta-stable structures, such as chemical short-range order, and kink bands has been shown to be a promising strategy to further improve the mechanical properties of HEAs. Full article

Background/Objectives: Radiomics has seen substantial growth in medical imaging; however, its potential in optical coherence tomography (OCT) has not been widely explored. We systematically evaluate the repeatability and reproducibility of handcrafted radiomics features (HRFs) from OCT scans of benign nevi and examine the impact of bin width (BW) selection on HRF stability. The effect of using stable features on a radiomics classification model was also assessed. Methods: In this prospective study, 20 volunteers underwent test–retest OCT imaging of 40 benign nevi, resulting in 80 scans. The repeatability and reproducibility of HRFs extracted from manually delineated regions of interest (ROIs) were assessed using concordance correlation coefficients (CCCs) across BWs ranging from 5 to 50. A unique set of stable HRFs was identified at each BW after removing highly correlated features to eliminate redundancy. These robust features were incorporated into a multiclass radiomics classifier trained to distinguish benign nevi, basal cell carcinoma (BCC), and Bowen’s disease. Results: Six stable HRFs were identified across all BWs, with a BW of 25 emerging as the optimal choice, balancing repeatability and the ability to capture meaningful textural details. Additionally, intermediate BWs (20–25) yielded 53 reproducible features. A classifier trained with six stable features achieved a 90% accuracy and AUCs of 0.96 and 0.94 for BCC and Bowen’s disease, respectively, compared to a 76% accuracy and AUCs of 0.86 and 0.80 for a conventional feature selection approach. Conclusions: This study highlights the critical role of BW selection in enhancing HRF stability and provides a methodological framework for optimizing preprocessing in OCT radiomics. By demonstrating the integration of stable HRFs into diagnostic models, we establish OCT radiomics as a promising tool to aid non-invasive diagnosis in dermatology. Full article

Background. Complete basal cell carcinoma (BCC) excision remains the most common treatment modality. However, its clinical characteristics and the surgical outcomes achieved in patients over 80 years—often with several medical comorbidities and potentially limited life expectancy—have not been thoroughly examined. This clinical study aims to investigate tumor-specific characteristics and surgical outcomes following surgical treatment of BCC in older individuals. Methods. An observational cohort study based on a prospectively maintained database was conducted in a tertiary center using a predetermined protocol. Patients who underwent BCC surgery between January 2010 and September 2024 were included and grouped by age under or over 80 years. The inclusion criterion was a histologically confirmed BCC, while patients with syndromes predisposing BCC development were excluded. Results. Among the 1396 biopsy-proven BCCs, 35% of the patients were older than 80 years. No significant differences were observed in their baseline characteristics. The pathogenic capacity was greater in elderly patients, who exhibited higher rates of multiple and concurrent skin cancers, larger BCC diameters, and routine involvement in high-risk areas. More lesions were classified as high-risk for recurrence, and the surgical treatment was accompanied by a higher frequency of positive or close margins, high-grade subtypes, and perineural invasion. Logistic regression of 1150 BCCs revealed that age > 80, advanced TNM stage, and margin status robustly predict high-risk histology and high NCCN risk of tumor recurrence. Conclusions. This study highlights that BCC in the elderly population tends to present with a more aggressive tumor status, based on the key clinical and pathology features. These findings underscore the need for tailored surgical strategies in this population. Full article

We investigated the hysteresis, pseudo-critical, and compensation behaviors of a quasi-spherical FeCo alloy nanoparticle (2 nm in diameter) using Monte Carlo simulations with thermal bath-type algorithms and a 3D mixed Ising model. The nanostructure was modeled in a body-centered cubic lattice (BCC) through the following configurations: spin $S=3/2$ for Co and $Q=2$ for Fe. These simulations reveal that, under the influence of crystal and magnetic fields, the nanoparticle exhibits compensation phenomena, exchange bias, and pseudo-critical temperatures. Knowledge of this type of phenomena is crucial for the design of new materials, since compensation temperatures and exchange bias improve the efficiency of advanced magnetic devices, such as sensors and magnetic memories. Meanwhile, pseudo-critical temperatures allow the creation of materials with controlled phase transitions, which is vital for developing technologies with specific magnetic and thermal properties. An increase in single-ion anisotropies within the nanosystem leads to higher pseudo-critical and compensation temperatures, as well as superparamagnetic behavior at low temperatures. Full article

The emergence of systemic therapies and photoprotection against non-melanoma skin cancer (NMSC) raises questions on the broader systematic impact of the disease. Personalized medicine involves a holistic patient approach, through which the evaluation of systemic biomarkers can reveal the interconnected aspects of patient health and tailored therapies. Cumulative UV exposure disrupts redox equilibrium and triggers inflammation and cutaneous immunosuppression, processes that contribute independently or via their interplay to cutaneous carcinogenesis. This systemic impact can be further reinforced by biomolecules derived from the NMSC microenvironment, fueling a continuous cycle of oxidative stress and inflammation in the organism. Regarding investigation of the systemic burden of NMSC, we conducted a narrative review focusing on parameters related to redox status, inflammation, and immune suppression observed in the blood components (serum, plasma, and erythrocytes) of NMSC patients. Our findings revealed an association of NMSC patients with perturbations of redox homeostasis, as evidenced by the decreased antioxidant activity, lower levels of non-enzymatic antioxidants, and increased byproducts of lipid, protein, and DNA oxidative damage. Additionally, NMSC patients presented augmented levels of pro-inflammatory interleukins, reduced anti-tumor biomolecule levels, and enhanced immune response markers, as well as elevated vitamin D levels. These systemic changes may lead to the association of NMSC with a higher risk of secondary malignancies in other organs. Overall, the findings of the present study suggest that NMSC affects systemic health beyond the skin, underscoring the need for a comprehensive and individualized approach to the management and monitoring of the patient. Full article

Laser powder bed fusion (L-PBF) is a widely used additive manufacturing technique that enables the creation of complex lattice structures with applications in biomedical implants and aerospace components. This study investigates the impact of relative density and the geometric parameters (unit cell size and strut diameter) of body-centred cubic (BCC) lattices on the compressive mechanical properties of Ti-6Al-4V (Ti64) lattices manufactured using continuous wave L-PBF. The as-built and heat-treated samples were evaluated for their Young’s modulus, strength, and ductility. Lattices with varying unit cell sizes (1–3 mm) and strut diameters (0.3–1.2 mm) were fabricated, resulting in relative densities ranging from 10% to 77%. All of these samples exhibited a 45° shear failure, which was attributed to the alignment of the principal stress planes with the lattice struts under compression, leading to shear band formation. This study provides critical insights into the interplay between geometric parameters, microstructure evolution, and resultant mechanical properties, contributing to the experimental validation of solid vs. lattice samples fabricated under identical conditions. Fractography analysis revealed that the as-built samples exhibited predominantly brittle fracture characteristics, while heat-treated samples displayed mixed fracture modes with increased ductility. Results indicate that heat treatment enhances mechanical properties, yielding comparable compressive strength (approx. 20% decrease), a reduced modulus of elasticity (approx. 30% decrease), and increased ductility (approx. 10% increase). This is driven by microstructural changes, such as the phase transformation from α’ martensitic needles to α + β, and thus relieves the residual stress to some degree. By addressing the microstructure–property correlations and failure mechanisms, this work establishes guidelines for optimizing lattice designs for biomedical and aerospace applications, emphasizing the critical role of geometric parameters and thermal treatment in tailoring mechanical behaviour. Full article

The Hedgehog (Hh) signaling pathway plays a crucial role in the initiation and progression of tumors, and Hh inhibitors have been used as potential chemotherapeutic agents for the treatment of basal cell carcinomas (BCCs). Vitamin D₃ (VD₃) and its derivatives have been identified as potent Hh inhibitors. However, the selectivity of VD₃ derivatives to vitamin D receptor (VDR) and the Hh signaling pathway still needs optimization. In this study, a series of aromatic A-ring mimics VD₃ analogues that contain a C-23 oxygen atom or incorporate C-25 hydroxyl on side chains were designed and synthesized. These compounds were tested in various cell lines for anti-Hh activity, with analogues 3j and 4i identified as potent inhibitors. Mechanism studies showed their anti-Hh effects are mainly due to targeting Smoothened (Smo) without binding to the cyclopamine site. Structure-activity relationship (SAR) studies revealed that VD₃-based inhibitors enhance anti-Hh activity by adding a hydroxyl group at C25 while reducing VDR activity by incorporating an oxygen atom into the side chain. Full article

Background: Soil salinity poses a significant threat to agricultural lands by adversely affecting soil properties, crop productivity, and, consequently, global food security. This study evaluated the effects of date palm waste compost (C), applied alone or combined with biochar (BCC) or Ramial chipped wood (RCWC), on soil properties and barley yield under arid and saline conditions. Methods: A field experiment was performed in a completely random design with three replications. In addition to the unamended soil (control), treatments with compost (C), biochar + compost (BCC) and Ramial chipped wood + compost (RCWC) were tested. We monitored soil physico-chemical parameters, straw biomass, grain yield, and soluble sugar levels over two crop seasons. Results: All treatments enhanced soil fertility. However, the sodium adsorption ratio (SAR) and the cation ratio of soil structural stability (CROSS) increased in soils amended with compost alone in the second crop year. Barley (Hordeum vulgare L.) cultivated in soil amended with C and BCC produced 28% and 37% more dry biomass, respectively, in the second year, while no significant effects were observed in the first year. This may be attributed to the higher availability of nutrient content (N and P) in soils during the second year. In the first year, plants amended with BCC exhibited the highest accumulation of sucrose and fructose, with increases of up to 39% and 66%, respectively. Conclusions: Compost application did not affect barley yield during the first crop year, highlighting limited effects on soil fertility. However, C and BCC improved barley yield in the second year after application. No synergistic effect was observed between biochar, Ramial chipped wood, and compost. Future Perspective: Further studies should focus on the long-term effects of organic soil management, including salinity issues, to support sustainable agriculture in arid regions. Full article