Search Results (282)

Neural crest cells give rise to the craniofacial skeleton and multiple pigment cell lineages, yet how duplicated developmental regulators partition their ancestral functions after teleost-specific whole-genome duplication remains unclear. Here, we employed CRISPR/Cas9 to generate alx4a and alx4b single and double mutants in Nile tilapia (Oreochromis niloticus). By integrating phenotype, skeleton, transcriptome, quantitative PCR, and AlphaFold-based structural modeling analyses, we revealed their functional divergence. Loss of alx4a caused a regionally restricted reduction in iridophore-derived reflectance and abnormal cranial morphology, whereas alx4b single mutants showed no obvious phenotype under the conditions examined. By contrast, double mutants exhibited an almost complete loss of iridophore-derived structural coloration and substantially more severe cranial defects, accompanied by reduced calcein labeling in the opercular region, consistent with altered cranial mineralization. Skin transcriptomic and quantitative PCR analyses revealed marked downregulation of pnp4a and tfec, which are associated with iridophore differentiation and coloration, whereas no significant expression differences were detected for the iridophore survival-related genes ltk and mpv17. AlphaFold2-assisted HDOCK protein–DNA modeling yielded more favorable docking metrics for Alx4a than for Alx4b with the pnp4a promoter, supporting a potential Alx4a–pnp4a promoter interaction that requires experimental validation. In contrast, no significant genotype-dependent differences were detected in the measured abundance of melanophores, xanthophores, or erythrophores, and no obvious difference in gross dorsal-fin spine formation was observed under the conditions examined. Together, these findings reveal unequal functional contributions of alx4a and alx4b, with alx4a acting as the dominant paralog in iridophore-associated structural coloration and both paralogs contributing unequally to cranial development, and support pnp4a as a candidate downstream gene associated with Alx4a activity. Full article

Background: Chronic nasopharyngeal inflammation (chronic epipharyngitis) is associated with various upper airway and systemic symptoms. However, the relationship between endoscopic inflammatory findings and functional respiratory abnormalities remains unclear. This study aimed to evaluate respiratory oscillometry parameters measured by the MostGraph system in patients with chronic epipharyngitis and to investigate their changes following Epipharyngeal Abrasive Therapy (EAT). Methods: In this retrospective observational study, patients diagnosed with chronic epipharyngitis who underwent MostGraph examination were analyzed. Respiratory resistance and reactance parameters, including R5−R20, X5, inspiratory X5 (Xin5), resonant frequency (Fres), and low-frequency reactance area (ALX), were assessed. Endoscopic findings were scored using a standardized grading system. Comparisons were performed between patients and healthy controls, and pre- and post-EAT measurements were evaluated. Correlations between endoscopic severity and oscillometric parameters were analyzed using Spearman’s rank correlation coefficient. Results: Patients with chronic epipharyngitis demonstrated significant abnormalities in oscillometric reactance parameters compared with healthy controls. Following EAT, a significant change was observed in R5−R20, whereas other oscillometric parameters did not show significant changes. In addition, endoscopic severity scores showed no significant correlation with oscillometric measurements. These findings suggest that respiratory oscillometry may detect physiological abnormalities that are not directly reflected by endoscopic inflammatory severity. Conclusions: Patients with chronic epipharyngitis exhibited abnormalities in respiratory oscillometry parameters despite the absence of significant associations with endoscopic severity scores. The observed dissociation between endoscopic findings and oscillometric measurements suggests that morphological inflammation and physiological dysfunction may represent distinct dimensions of the disease. Respiratory oscillometry may therefore provide complementary information regarding the pathophysiology of chronic epipharyngitis beyond conventional endoscopic assessment. Full article

This study presents a comparative machine-learning investigation for predicting the optical absorption coefficient of truncated pyramidal GaN/Al_xGa_1−xN quantum dots. The physical dataset is generated by solving the three-dimensional Schrödinger equation using a coordinate-transformation method combined with the finite-difference method (FDM). The coordinate transformation maps the sloping boundaries of the truncated pyramidal geometry onto a regular computational domain, enabling an accurate representation of the quantum-dot shape and facilitating its numerical treatment using the FDM. The absorption coefficient is then calculated as a function of photon energy for different alloy compositions. Using photon energy and alloy composition as input features, Artificial Neural Network (ANN), Random Forest (RFR), Decision Tree (DT), and k-Nearest Neighbor (KNN) models are developed and evaluated. A second-degree polynomial regression model is also considered as a classical baseline. Under the point-wise random 80/20 split, all models show excellent agreement with the numerical results, with $R^2$ values close to unity. KNN generally provides the lowest prediction errors across most alloy compositions, whereas ANN achieves slightly lower MSE and RMSE values at $x=0.5$. Furthermore, leave-one-composition-out validation identifies ANN as the most effective model for predicting unseen compositions, achieving a mean $R^2$ of 0.848 and an NRMSE of 7.19%. These findings demonstrate that KNN is particularly effective for local interpolation within the sampled domain, while ANN provides stronger composition-wise generalization. The proposed framework offers an efficient surrogate for computationally demanding numerical simulations of the optical properties of quantum nanostructures. Full article

Amorphous metal alloys (AMAs) are metastable materials that are characterized by good mechanical properties and corrosion properties. It is known that with certain thermal modifications, these properties improve or lose their value. The purpose of this research work is to investigate the optimal conditions of thermal modification that improve the mechanical properties of this alloy. The DSC method established the temperatures of phase transitions in the temperature range of 624–643 K, which correspond to the following processes: crystal nucleation (T₁ = 624 ± 1 K), growth (T₂ = 633 ± 1 K), and stable crystallization (T₃ = 643 ± 1 K). The XRD and TEM/HREM methods revealed structural changes in the amorphous matrix as a result of thermal modification. As a result of isothermal annealing for 2 min. at temperatures T₁, T₂, T₃, a solid solution based on aluminum and a thermally stable compound Al₁₉Ni₅(Y,Gd)₃ were formed. The equation for the transformation of an amorphous matrix AMA Al₈₇Y₄Gd₁Ni₈ in the temperature range (624–643) ± 1 K during isothermal 2 min annealing is given by: Am → Am′_resid+ solid solution Al(X) → Am′_{(enriched REE)} + solid solution Al(X) + nano-Al₁₉Ni₅(Y,Gd)₃ → Am′_{(enriched REE)} + solid solution Al(X) + nano-Al₁₉Ni₅(Y,Gd)₃. The Oliver–Pharr method established that AMAs annealed at temperatures T₁ and T₂ have microhardness indicators 5–9 times higher than amorphous samples; however, the material loses its elasticity under such thermal deformation conditions. Full article

Ruminants are unique among living mammals in possessing paired bony cranial appendages in the form of horns, pronghorns, antlers, or ossicones. This review summarizes current knowledge on the structure, development, function, and evolution of these appendages and integrates recent findings from genomics, transcriptomics, and single-cell analyses. Two competing hypotheses have been proposed to explain their origin. According to the independent-origin hypothesis, horns, pronghorns, antlers, and ossicones evolved separately in different pecoran lineages, possibly through repeated recruitment of similar developmental capacities of the frontal region of the skull. According to the common-origin hypothesis, these appendages derive from a single ancestral osseous cranial structure that was subsequently modified in different lineages. Comparative anatomy and developmental data reveal major differences among the four types of appendages, including dermally ossifying horn cores in bovids, annually regenerated antlers arising from frontal bone pedicles in cervids, deciduous keratin sheaths in pronghorns, and skin-covered ossicones in giraffids. The fossil record does not currently resolve these hypotheses, because the main appendage types are first documented within a relatively short early Miocene interval and transitional forms remain unknown. In contrast, molecular and cellular studies identify shared developmental pathways, cranial neural crest-derived progenitors, and conserved regulatory genes, including RXFP2, ALX1, SOX9, and components of Wnt signaling, which are consistent with a shared developmental module. We conclude that the homology of pecoran cranial appendages remains unresolved and that further paleontological, developmental, and comparative molecular studies are required to determine whether these structures share a common evolutionary origin or instead represent convergent recruitment of similar developmental programs. Full article

Body color brightness is a key determinant of ornamental value in koi, yet nutritional strategies targeting structural coloration mediated by iridophores remain underexplored. Fish scale meal (FSM), an abundant fishery by-product, contains guanine and collagen, which may contribute to structural coloration and body brightness. This study evaluated the effects of partial replacement of fish meal with FSM on growth performance, body color parameters, pigment accumulation, iridophore density, and iridophore-related gene expression in koi. A total of 384 koi with an initial body weight of 19.02 ± 0.18 g were randomly assigned to six dietary treatments for 8 weeks, with FSM inclusion levels ranging from 0% to 9.55%, corresponding to 0–100% replacement of dietary fish meal. Growth performance, including final body weight, weight gain rate, and specific growth rate, decreased with increasing FSM inclusion. Body lightness (L*) and scale guanine content increased progressively with FSM level and reached their highest values at 9.55% FSM, whereas redness (a*), yellowness (b*), and total carotenoid content showed the opposite trend. Iridophore density was significantly higher in the 3.82–5.73% FSM groups than in the other treatments. The expression of iridophore-related genes, including sox10, pax3, ltk, alx4a, and foxd3, showed non-linear responses and generally reached higher levels at moderate FSM inclusion, whereas pka showed an opposite transcript pattern. Overall, dietary FSM inclusion elicited trait-dependent responses in koi. Low or no FSM inclusion was preferable for maintaining growth, intermediate inclusion was more favorable for iridophore development, whereas higher FSM inclusion enhanced brightness-related traits. These findings suggest that FSM should be used according to the intended production objective, with inclusion levels adjusted for growth maintenance, iridophore-related coloration improvement, or brightness enhancement. Full article

FeAl_xO_y powders, fabricated by solution combustion synthesis (SCS), are promising catalysts for microwave-assisted pyrolysis of methane. However, the effects of SCS parameters on the pyrolysis are not well understood. In the present work, two fuels (citric acid and glycine), two Fe:Al molar ratios, and two heating modes (a hotplate and a muffle furnace) are tested. All catalysts exhibit CH₄ conversion of around 70% and H₂ composition of about 93%. The process is one to two orders of magnitude more efficient than conventional pyrolysis. Increasing the Fe:Al ratio from 1:1 to 2:1 and using a hotplate improve H₂ generation efficiency. Use of glycine decreases the CO₂:H₂ ratio, but citric acid yields more readily reducible products due to differences in phase evolution, detected by X-ray diffraction analysis. Scanning electron microscopy and energy-dispersive X-ray spectroscopy reveal carbon nanotubes and exsolution of Fe. FeAl_xO_y catalysts, prepared via incipient wetness impregnation, are ineffective. Full article

CoCrNiTiAl_x high-entropy alloy films with varied Al contents were fabricated on 42CrMo steel substrates via magnetron sputtering. By adjusting the sputtering power of the Al target, an investigation was systematically carried out to explore the effect of different Al contents on the microstructural evolution, mechanical properties, and corrosion resistance of the film, with the underlying synergistic mechanism governing these properties being elucidated. With increasing Al content, the film microstructure gradually transforms from an amorphous phase at low Al contents to a nanocrystalline–amorphous composite structure, until it is converted into the BCC phase, and the film’s crystallinity exhibits a trend of first increasing and then decreasing. In terms of mechanical properties, the film hardness is significantly enhanced from 7.6 ± 1.3 GPa to 18.9 ± 1.1 GPa with increasing Al content, while the toughness gradually declines. Wear tests show that the film wear rate first decreases and then increases with rising Al content, reaching a minimum of 2.06 × 10⁻⁵ mm³/N·m. The superior protective state, characterized by a corrosion potential reaching −361.2 mV and corrosion current density dropping to 1.12 μA/cm², arises from the generation of an integrated, consistently structured composite passivation barrier in 3.5 wt.% solution. This study confirms that appropriate Al doping can synergistically optimize the microstructure, mechanical properties, and corrosion resistance of CoCrNiTiAl_x films, providing experimental and theoretical support for the compositional design and engineering applications of high-performance high-entropy alloy protective films. Full article

In this work, the structural, optical, vibrational, and stability properties of a series of Al_xAs_x nanostructures are systematically investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Starting from the fundamental cubic-like Al₄As₄ building block, progressively larger nanostructures were constructed through directional elongation and structural rearrangements, allowing for the exploration of one-dimensional chains, two-dimensional planar structures, and several exotic geometries. The calculated UV–visible absorption spectra reveal that structural dimensionality and topology strongly influence the electronic transitions of the nanostructures, with elongated and distorted configurations exhibiting broader absorption features and richer spectral distribution. Vibrational analysis shows that increasing structural complexity and reducing symmetry lead to a higher density of IR-active modes and more complex infrared spectra. The stability of the nanostructures is evaluated through binding energy calculations, which indicate a clear size-dependent stabilization trend, with the Al₂₄As₂₄-L1 configuration exhibiting the highest stability among the examined systems. In addition, the calculated HOMO-LUMO gaps reveal the semiconducting character of the clusters and demonstrate their sensitivity to geometric topology. The present results establish clear structure–property relationships between dimensional growth and the optical response of AlAs nanoparticles and provide theoretical reference data for future experimental investigations of III-V semiconductor nanostructures. Full article

In this work, we develop machine-learned moment tensor potentials (MTPs) to simulate the static and dynamic structural properties in Al_xGa_1−xN and related materials. The potentials are trained on DFT-calculated data for forces, stresses, and energies obtained from random atomic displacements and cell deformations. MTP-calculated physical properties, including lattice parameters and elastic constants, thermal expansion, harmonic and anharmonic vibrational properties, and the thermal conductivity, are benchmarked against first-principles results and experimental data. The comparisons testify to the very high accuracy achieved by the machine-learned potentials despite the massively reduced computational effort. Additionally, the impact of various aspects of the MTP training procedure is examined. Full article

SiC fiber-reinforced aluminum matrix (SiC_f/Al) composites have the potential to replace titanium alloys for fan/compressor blades due to their low density and favorable high-temperature performance. In this study, thermal exposure and thermal cycling tests were conducted to simulate service environments and to clarify their effects on the microstructure and interfacial properties of a SiC_f/AlFe5Si2 composite. Thermal exposure was performed at 260–450 °C for 20–100 h, and thermal cycling was carried out between 300 or 350 °C (1 h dwell) and room temperature for 20–100 cycles. Interfacial shear strength was evaluated by push-out tests, while microstructural evolution was examined using SEM, TEM/EDS, and XRD. Three-dimensional finite element simulations were used to assess mismatch-driven residual-stress distributions during the cooling stage after thermal excursion. The results showed that interfacial shear strength decreased with increasing exposure temperature/time and degraded more severely under thermal cycling than under isothermal exposure at the same temperature. A rapid loss of interfacial strength occurred above ~400 °C, associated with significant interfacial-layer thickening and the formation of brittle Al_xSiO_y phases. The interfacial reaction layer followed parabolic growth kinetics, yielding a preliminary apparent activation energy of Q ≈ 150 kJ/mol estimated from two isothermal temperatures. The simulations indicated large opposing stresses between the matrix and the carbon-rich layer, supporting a mechanical driving force for interfacial debonding; however, heating/dwell time-dependent effects were not explicitly modeled and are discussed as limitations. These findings provide quantitative guidance for defining service-temperature limits and improving interfacial thermal stability in SiC_f/AlFe5Si2 composites. Full article

Fe-Cr-based alloys have great potential for large-scale vibration and noise reduction. Appropriate heat treatment is important for improving their damping capacity. However, M₂₃C₆-type carbides are common grain boundary precipitates during the heat treatment process, and can affect both damping behavior and mechanical properties. In this work, the effects of Al content and annealing temperature on the microstructure, internal friction (IF), room temperature damping capacity, and tensile properties of Fe-15Cr-(0-4) Al (wt.%) alloys were investigated. When annealed at 800 °C, Al addition can suppress grain boundary precipitation, and no obvious intergranular precipitates were observed in the S2Al-S4Al alloys. The ultimate tensile strength also increased with Al addition, and the S4Al alloy exhibited a 34% higher strength than S0Al while retaining an elongation of 47.7%. The maximum damping value increased with Al addition. However, annealing at 1000 °C promoted continuous grain boundary carbide formation and reduced the elongation. These results indicate that the S4Al alloy annealed at 800 °C provides a favorable balance between damping capacity and mechanical properties. Full article

Josephson junctions are key elements in superconducting qubits. Their efficient wafer-scale characterization is crucial for process control and optimization, motivating analysis approaches that extend beyond conventional cryogenic measurements. In this work, we demonstrate that room temperature (RT) capacitance and current–voltage measurements, combined with appropriate data analysis, enable extraction of relevant junction parameters such as oxide thickness, tunnel coefficient, and interfacial defect density. Furthermore, different charge transport mechanisms can be identified from detailed current–voltage analysis. We evaluate our characterization technique using tunnel junctions fabricated on 200 mm wafers in a complementary metal–oxide–semiconductor (CMOS)-compatible subtractive process. The results show a homogeneous average oxide thickness across the wafer with a variation below 3%. A dependence of the tunnel coefficient on oxide thickness indicates a stoichiometry gradient within the oxide. Additionally, low interfacial defect densities in the range of 70–5000 defects/cm² are observed in our junctions, increasing with decreasing oxide thickness, suggesting that wet etching used for thickness control introduces interfacial trap states. Our study highlights the importance of advanced RT characterization for extracting tunnel junction parameters on the wafer scale, enabling effective process monitoring and optimization in industrial superconducting qubit manufacturing. Full article

The microstructure, phase composition, and high-temperature oxidation behavior of Al_0.5CoCr_0.5NiPt_0.1 and AlCoCr_0.5NiPt_0.1 multi-principal element alloys (MPEAs) at 1100 °C in air were investigated. Depending on the content of aluminum, the microstructure of as-cast samples contains FCC and BCC solid solutions. Similarly, the ratio of two solid solutions varies depending on the aluminum content in the alloy. When the content of aluminum is x = 0.5, the microstructure is dominated by the FCC solid solution, while a BCC solid solution is dominated when the concentration of aluminum is increased to x = 1.0. Moreover, in both MPEAs, platinum exists as a part of solid solutions rather than a separate phase. High-temperature oxidation was carried out in a Plavka.Pro PM-1 SmartKiln muffle furnace under isothermal conditions at 1100 °C for 100 h exposure in air, and weighing was performed every 10 h. The maximum specific weight gain for the Al_0.5CoCr_0.5NiPt_0.1 alloy was 0.965 mg/cm², and 0.675 mg/cm² for the AlCoCr_0.5NiPt_0.1 alloy. Based on the high-temperature oxidation experiment results, it was established that AlCoCr_0.5NiPt_0.1 MPEA exhibits greater resistance towards high-temperature dry air corrosion with the formation of an exclusive Al₂O₃ scale on the surface with 3–5 μm thickness; the parabolic oxidation rate constant for this alloy is k_p = 20.2 × 10^–13 (g²/cm⁴s). Introduction of platinum into the composition of the Fe-free AlCoCr_0.5Ni alloy reduces the value of the parabolic oxidation rate constant by half. Full article

TiN/CrAlN multilayer coatings were synthesized by cathodic arc deposition using 2-fold substrate rotation and alternating targets. The effect of substrate rotation on the layer sequence, elemental fluctuations and interface quality was examined using high-resolution transmission electron microscopy and atom probe tomography. The layers exhibited semi-coherent growth across the interfaces. Minor interface roughness and elemental intermixing limited to below 2 nm at the interface could be observed. Further, the formation of a Ti-enriched sublayer in the Cr_1−xAl_xN as a result of the 2-fold rotation was identified. Full article