Search Results (228)

Background/Objectives: Spanish-speaking patients face persistent barriers in accessing equitable audiological care, particularly when standardized language-appropriate tools are lacking. Two Spanish-language sentence recognition tests, the Spanish AzBio Sentence (SAzB) and the Latin American Hearing in Noise Test (LAH), are commonly used to evaluate speech perception in adults with hearing loss. However, performance differences between these measures may influence referral decisions for hearing intervention, such as cochlear implantation. This study compared test performance under varying noise and spatial conditions to guide appropriate test selection and reduce the risk of misclassification that may contribute to healthcare disparities. Methods: Twenty-one bilingual Spanish/English speaking adults with normal bilateral hearing completed speech perception testing using both the SAzB and LAH. Testing was conducted under two spatial configurations: (1) speech and noise presented from the front (0° azimuth) and (2) speech to the simulated poorer ear and noise to the better ear (90°/270° azimuth). Conditions included quiet and three signal-to-noise ratios (+10, +5, and 0 dB). Analyses included paired t-tests and one-way ANOVAs. Results: Participants scored significantly higher on the LAH than on the SAzB across all SNR conditions and configurations, with ceiling effects observed for the LAH. SAzB scores varied by language dominance, while LAH scores did not. No other differences were observed based on any further demographic information. Conclusions: The SAzB provides a more challenging and informative assessment of speech perception in noise. Relying on easier tests like the LAH may obscure real-world difficulties and delay appropriate referrals for hearing loss intervention, including cochlear implant evaluation. Selecting the most appropriate test is critical to avoiding under-referral and ensuring Spanish-speaking patients receive equitable and accurate care. Full article

Magnesium alloys, like AZ31, possess a desirable low weight and high specific strength, which make them favorable for aerospace and auto applications, yet their difficulty to machine limits their broader implementation for the industry. Electrical discharge machining (EDM) is an effective technology for machining difficult-to-machine materials, particularly when the materials are reinforced with ceramic and graphene-based fillers. This study examines the impact of reinforcement percentage (R) and different electrical discharge machining (EDM) parameters such as current (I), pulse on time (T_on) and pulse off time (T_off) on the material removal rate (MRR) and surface roughness (SR) of AZ31/B₄C/GNPs composites. The combined reinforcement range varies from 2 wt.% to 4 wt.%. The Taguchi design (L27) is utilized to conduct the experiments in this study. ANOVA of the experimental data indicated that current (I) significantly affects MRR and SR, exhibiting the greatest contribution of 44.93% and 51.39% on MRR and SR, respectively, among the variables analyzed. The surface integrity properties of EDMed surfaces are examined using SEM under both higher and lower material removal rate settings. Diverse machine learning techniques, including linear regression (LR), polynomial regression (PR), Random Forest (RF), and Gradient Boost Regression (GBR), are employed to construct an efficient predictive model for outcome estimation. The built models are trained and evaluated using 80% and 20% of the total data points, respectively. Statistical measures (MSE, RMSE, and R²) are utilized to evaluate the performance of the models. Among all the developed models, GBR exhibited superior performance in predicting MRR and SR, achieving high accuracy (exceeding 92%) and lower error rates compared to the other models evaluated in this work. This work demonstrated the synergy between techniques in optimizing EDM performance for hybrid composites using a statistical design and machine learning strategies that will facilitate greater use of hybrid composites in high-precision engineering applications and advanced manufacturing sectors. Full article

To explore the influence of the microstructure of plasma electrolytic oxidation (PEO) coating on the loading of corrosion inhibitors and the silanization treatment on its surface, PEO coatings were first prepared on the surface of AZ31B magnesium alloy under different voltages. Secondly, sodium tungstate (Na₂WO₄) was loaded into the micropores and onto the surface of the PEO coatings via vacuum impregnation, and which were subsequently subjected to silanization treatment. The phase composition of the coatings was studied by XRD, while the elemental composition and valence state were investigated by XPS. The surface and cross-sectional morphology of the coatings, as well as the composition and distribution of elements, were studied by SEM and EDS. Image J software was employed to analyze the thickness of the coatings. The results show that the microstructure of PEO coatings prepared under different voltages varies, which affects the loading of Na₂WO₄ on the surface of PEO coating and the sealing effect of silanization treatment, thereby influencing the corrosion resistance of the coatings. As the voltage increases, the coating thickness and roughness gradually increase, while the surface porosity first increases and then decreases, and the loaded content of Na₂WO₄ also follows a trend of first increasing and then decreasing. Meanwhile, at 300 V and 350 V, silanization treatment effectively seals the PEO coatings loaded with Na₂WO₄. However, when the voltage increases to 400 V, due to the uneven surface of the PEO coating, nonuniform distribution of micropores, and high roughness, the silanization treatment fails to completely cover the coating. This results in defects such as pits on the surface of the composite coating prepared at 400 V. Therefore, the composite coating prepared at 350 V exhibits the best corrosion resistance. After immersion in a 3.5 wt.% NaCl solution for 240 h, the composite coating formed at 350 V remains intact, and its low-frequency impedance modulus |Z|_0.01Hz is as high as 1.06 × 10⁶ cm². This value is approximately two orders of magnitude higher than that of the composite coating fabricated at 400 V and about three orders of magnitude higher than that of the pure PEO coating prepared at 350 V. Full article

Background: The anterior cerebral artery (ACA), a critical component of the cerebral arterial circle, exhibits substantial morphological variability. While previous studies have explored ACA morphology using cadaveric and imaging methods, a comprehensive meta-analysis incorporating the latest evidence is lacking. Methods: Following current guidelines, a systematic review and meta-analysis were performed across four major databases, supplemented by the gray literature and targeted journal searches. Ninety-nine studies, encompassing 85,316 patients, met the inclusion criteria. Statistical analyses were conducted using R, applying random effects models to estimate pooled prevalence and morphometric parameters. Results: The pooled prevalence of typical ACA morphology was 93.75%, whereas variants were noted in 6.25% of cases. The predominant variation identified was the accessory ACA (aACA) (1.99%), followed by unilateral absence of the A1 segment (1.78%), with the latter being more frequently recognized in imaging studies (p < 0.0001). Rare variants encompassed azygos ACA (azACA) (0.22%), fenestrated ACA (fACA) (0.02%), and bihemispheric ACA (bACA) (0.02%). The mean diameter and length of the A1 segment were measured at 2.10 mm and 14.24 mm, respectively. Hypoplasia of the A1 segment (<1 mm diameter) was recorded in 3.15% of cases. The influences of imaging modality, laterality, and population distribution on prevalence estimates were minimal. No significant publication bias was detected. Conclusions: Although infrequent, variants of the ACA possess significant clinical importance attributable to their correlation with aneurysm formation and the impairment of collateral circulation. The aACA and the absence of the A1 segment emerged as the most common variations. This meta-analysis presents an updated and high-quality synthesis of ACA morphology, serving as a valuable reference for clinicians and anatomists. Full article

The histone H2A variant H2AZ plays pivotal roles in shaping chromatin architecture and regulating gene expression. We recently identified H2AZ.2 in histone H2A lysine 119 ubiquitination (H2AK119ub)-enriched nucleosomes, but it is not known whether its highly related isoform H2AZ.1 also regulates this modification. In this study, we employed isoform-specific epitope-tagged knock-in mouse embryonic stem cell (ESC) lines to dissect the roles of each isoform in Polycomb Repressive Complex 1 (PRC1)-mediated H2AK119ub. Our results show that H2AZ.1 and H2AZ.2 share highly overlapping genomic binding profiles, both co-localizing extensively with H2AK119ub-enriched loci. The knockdown of either isoform led to reduced H2AK119ub levels; however, the two isoforms appear to function through distinct mechanisms. H2AZ.1 facilitates the recruitment of Ring1B, the catalytic subunit of PRC1, thereby promoting the deposition of H2AK119ub. In contrast, H2AZ.2 does not significantly affect Ring1B recruitment but instead functions as a structural component that stabilizes H2AK119ub-modified nucleosomes. In vitro ubiquitination assays indicate that H2AZ.1-containing nucleosomes serve as more efficient substrates for PRC1-mediated ubiquitination compared to those containing H2AZ.2. Thus, these findings define the distinct mechanisms of the two H2AZ variants in regulated PRC1-mediated H2AK119 ubiquitination and highlight a functional division of labor in epigenetic regulation. Full article

Daucus is a large genus of the Apiaceae family, comprising around forty-five accepted species, that has a worldwide distribution. Species of this genus have been reported to have several traditional medicinal uses, and some of them are also largely used as food and spices. Daucus nebrodensis Strobl. is an endemic species of Sicily growing in the montane environments of the Madonie and the Nebrodi Mountains. In this work, the essential oil of D. nebrodensis (DnEO), collected wild near Messina (Italy), was chemically and biologically investigated. The hydrodistilled essential oil (yield 0.15%), obtained from fresh aerial parts, was evaluated by GC-MS, and It was particularly rich in monoterpene hydrocarbons, with sabinene (33.6%), α-pinene (17.2%), γ-terpinene (9.8%), and α-terpinene (7.6%) as the main metabolites. DnEO, and its main constituents, have been tested to evaluate their biological properties. Given the current problem of antibiotic resistance, it is of great interest to identify alternative molecules that could counteract the its progression. Therefore, DnEO was tested against Gram-negative species, such as E. coli DH5α and P. aeruginosa PAOI, and Gram-positive species, such as S. aureus ATCC6538P, B. subtilis AZ54, and M. smegmatis MC²155, showing notable antibacterial activity. The MIC for Bacillus subtilis, the most sensitive strain, was 18 mg/mL, while the MIC for Pseudomonas aeruginosa, the least sensitive strain, was 30 mg/mL. Moreover, interesting antibiofilm activity was observed against Mycobacterium smegmatis with a 55% inhibition. Its ability to form biofilms contributes to its persistence and resistance in clinical settings. These findings highlight the potential of D. nebrodensis EO as a source of bioactive compounds with promising antimicrobial and antibiofilm properties. Full article

Magnesium as a biodegradable metal implant has garnered attention. Nevertheless, its rapid degradation rate and insufficient osseointegration restrict its clinical applications. In order to enhance the corrosion resistance and bioactivity of magnesium alloys, superhydrophobic hydroxyapatite (HA) layers were synthesized on micro-arc oxidized (MAO)-treated AZ31B magnesium alloy through liquid-phase deposition. This study examined the surface morphology, phase composition, bonding strength, wettability, electrochemical properties, and in vitro mineralization of the synthesized coatings. The study results demonstrated that the improved corrosion resistance of composite coatings in Hank’s solution is due to the formation of a protective HA layer. The inclusion of the MAO coating significantly enhances the bonding strength between the hydroxyapatite (HA) layer and the bare magnesium alloy. The concentration of NaH₂PO₄ affects both the microstructure and wettability. The composite coating exhibited excellent osseointegration capabilities, with new HA layers observed after immersing the samples in simulated body fluid (SBF) solution for three days. These findings suggest that the combination of MAO and solution treatment presents a promising method for enhancing biocompatibility and reducing magnesium degradation, thus making it a viable option for biodegradable implant applications. Full article

This study presents a systematic investigation into the influence of pulse frequency on the micro-arc oxidation (MAO) coating of AZ31B magnesium alloy following electron-beam remelting (EBR). The morphology, thickness, and corrosion resistance of the EBR-MAO composite coating were meticulously analyzed across various pulse frequencies (100 Hz, 200 Hz, 300 Hz, 400 Hz) employing scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical measurement techniques. The results show that as the pulse frequency escalates from 100 Hz to 400 Hz, the average thickness of the EBR-MAO composite coating diminishes from 41.1 μm to 38.5 μm, reduced by 6.7% compared to 10.4% in the MAO coating. Concurrently, the porosity exhibits a reduction from 1.93% to 1.35%, accompanied by a densification of the coating’s structure. High pulse frequencies yield coatings with enhanced smoothness and fewer defects. Notably, the corrosion resistance of the coatings demonstrates significant improvement at higher frequencies (400 Hz) compared to their lower-frequency (100 Hz) counterparts, as evidenced by a tenfold increase in corrosion current density. This research underscores the pivotal role of pulse frequency in optimizing the protective qualities of MAO coatings on magnesium alloys. Full article

AZ31B magnesium alloy (wt.%: Al 2.94; Zn 0.87; Mn 0.57; Si 0.0112; Fe 0.0027; Cu 0.0008; Ni 0.0005; Mg remaining) has appropriate mechanical properties, good biodegradability and biocompatibility and can be used as a good orthopedic implant material. AZ31B magnesium alloy with a superhydrophobic surface exhibits excellent corrosion resistance and antibacterial adhesion performance, but superhydrophobic surfaces also hinder osteoblast adhesion and proliferation on the implants, resulting in unsatisfactory osteogenic properties. Therefore, it is necessary to achieve the wettability transition of the superhydrophobic surface at an early stage of implantation. In this work, superhydrophobic hydroxyapatite (HA)/calcium myristate (CaMS)/myristic acid (MA) composite coatings were prepared on AZ31B magnesium alloy using the hydrothermal and immersion methods. The composite coatings can spontaneously undergo the wettability transition from superhydrophobic to hydrophilic after complete exposure to simulated body fluid (SBF, a solution for modeling the composition and concentration of human plasma ions) for 9 h. The wettability transition mainly originated from the deposition and growth of the newly formed CaMS among the HA nanopillars during immersing, which deconstructed the micro-nano structure of the superhydrophobic coatings and directly exposed the HA to the water molecules, thereby significantly altering the wettability of the coatings. Benefiting from the superhydrophobic surface, the composite coating exhibited excellent antibacterial properties. After the wettability transition, the HA/CaMS/MA composite coating exhibited superior osteoblast adhesion performance. This work provides a strategy to enable a superhydrophobic coating to undergo spontaneous wettability transition in SBF, thereby endowing the coated magnesium alloy with a favorable osteogenic property. Full article

This paper presents research findings on the turning of AZ31B magnesium alloy using ceramic-coated tungsten carbide tool inserts in a dry environment. Fifteen experiments were conducted according to the Box–Behnken design (BBD) for the straight turning of AZ31B magnesium alloy to investigate the variations in two important machinability indicators, i.e., material removal rate ‘MRR’ and mean roughness depth ‘R_Z’, with variations in cutting speed ‘C_S’, feed rate ‘f_r’, and depth of cut ‘DoC’. The cutting speed and feed rate had the maximum influence on the mean roughness depth and material removal rate, respectively. To address the challenge of optimizing conflicting machining responses, desirability function analysis (DFA) and grey relational analysis (GRA) were employed to identify the optimal turning parameters for conflicting machinability indicators or responses. These techniques enabled the simultaneous maximization of the material removal rate and the minimization of the mean roughness depth, ensuring an effective balance between productivity and surface quality. The optimal turning conditions—cutting speed of 90 m/min, feed rate of 0.2 mm/rev, and depth of cut of 1.0 mm—yielded the best multiperformance results with an MRR of 18,000 mm³/min and an R_Z of 2.21 µm. Scanning electron microscope (SEM) analysis of the chip and flank surface of the cutting tool insert used in the confirmation tests revealed the formation of band-saw-type continuous chips and tool wear caused by adhesion and abrasion. Full article

This study explores the enhancement of photocatalytic activity in Zeolitic Imidazolate Framework-67 (ZIF-67), integrated with plasma electrolytic oxidation (PEO) coatings on an AZ31 magnesium alloy through post-treatment with potassium permanganate (KMnO₄). The KMnO₄ treatment induces the partial amorphization of ZIF-67, resulting in improved light absorption and the increased availability of catalytic sites. Structural and compositional analyses confirmed the formation of MnO_x species and amorphous domains that synergistically contribute to enhanced photocatalytic performance. Under visible light, the treated coatings demonstrated remarkable efficiency, degrading 99.43% of rhodamine B (RhB) dye within just 50 min, an improvement attributed to superior light absorption, enhanced charge separation, and the introduction of additional active sites. These findings establish KMnO₄ post-treatment as a transformative approach for optimizing MOF-based coatings, offering a pathway to develop advanced functional coatings with exceptional dye degradation capabilities. Full article

In this study, the strain distribution and microstructural evolution of the AZ31B magnesium alloy were analyzed via uniaxial tensile loading combined with an in situ tensile test. The results conclusively showed that the strain on the AZ31B magnesium alloy’s surface is not uniform during tensile loading in a specific direction, and the emergence of localized twins fosters the development of densely intersecting shear bands, whereas prismatic slip intensified the strain concentration within these bands, ultimately bolstering their strength. These densely packed, discrete shear bands exhibited a dual role: they stabilized plastic deformation processes while simultaneously contributing to material failure. By elucidating the intricate relationship between grain orientation, evolution of the microstructure, and mechanical properties, we could effectively mitigate the detrimental orientations and deformations in anisotropic-polycrystalline materials to enhance their plasticity. The research carries paramount scientific significance and is the key to maximizing the engineering application potential of the AZ31B magnesium alloy. Full article

This paper aimed to investigate the enhancement of the corrosion resistance of a protective system applied on the AZ31 magnesium alloy to be used as an orthopedic biomedical device, composed of three different superimposed layers: (a) magnesium-based oxide, (b) polydopamine, and (c) polylactic acid. Specifically, morphological and chemical analyses, crystallographic, roughness, and micro-hardness were carried out. The electrochemical measurements were performed in Hanks’ Balanced Salt solution at 37 °C. The micro arc oxidation (MAO) treatment involved the classic pancake structure of the oxide with a consequent high extension of the real area.The sealing ofits pores via the polydopamine was well highlighted through the surface roughness analysis. As expected, the magnesium oxide layer reduced the degradation rate.The presence of polydopamine on the oxide layer improved the corrosion resistance of the alloy, showing a pseudo-passivity range in the potentiodynamic polarization curve, due to the filling of oxide pores.The highest impedance modulus in the electrochemical impedance spectroscopy analysis during the temporal observation of 168 h was observed when all coatings were applied on magnesium substrate, due to a synergetic action. Thus, the multilayers should represent a protective system to control the degradation process. Full article

Currently, there are several drugs used for the treatment of type 2 diabetes (T2D); however, all of them have adverse effects. Benzothiazoles have a broad spectrum of biological activities such as antidiabetic. This study aimed to evaluate in silico and in vivo two series of 2-aminobenzothiazole derivatives linked to isothioureas (3a–w) or guanidines (4a–z) for the treatment of T2D. The ADMET properties were determined in silico, from which it was possible to select nine compounds (two isothioureas and seven guanidines), and, with molecular docking, it was shown that compounds methyl (E)-N′-(benzo[d]thiazol-2-yl)-N-methylcarbamimidothioate (3b) and 2-(benzo[d]thiazol-2-yl)-1,3-di-tert-butylguanidine (4y) showed a high affinity for PPARγ (ΔG = −7.8 and −8.4 kcal/mol, respectively). In vivo, the LD50 value was estimated in rats based on OECD Guideline 425, being >1750 mg/kg for both compounds. The pharmacological effect of 3b and 4y was evaluated in the T2D rat model, showing that after oral administration in an equimolar ratio to pioglitazone (15 mg/kg) for 4 weeks, both compounds were able to reduce blood glucose levels (<200 mg/dL) and improve the lipid profile. Therefore, 3b and 4y could be used in the future as antidiabetic agents. Full article

Osteoarthritis (OA), particularly in the knee and hip, poses a significant global health challenge due to limited therapeutic options. To elucidate the molecular mechanisms of OA and identify potential biomarkers and therapeutic targets, we utilized genome-wide association studies (GWAS) and cis-miRNA expression quantitative trait loci (cis-miR-eQTL) datasets to identify miRNAs associated with OA, revealing 16 that were linked to knee OA and 21 to hip OA. Among these, hsa-miR-1303 was significantly upregulated in both knee and hip OA (IVW: p = $6.8164\times {10}^{-36}$ and $4.7919\times {10}^{-2}$ respectively, OR > 1) and identified as a key factor in disease progression. Hsa-miR-1303 potentially regulates 30 genes involved in critical signaling pathways, such as the neurotrophin signaling pathway, and interacts with competing endogenous RNAs (ceRNAs) like circ_0041843 and LINC01338, thereby influencing key regulatory proteins such as SUMO2 and PARP1. Pharmacologically, hsa-miR-1303 targets nine druggable genes, including NRAS, H2AZ1, and RPS3, which have implications for drugs like cantharidin and diindolylmethane, potentially critical for developing novel OA treatments. Conversely, hsa-miR-125a-5p and hsa-miR-125b-5p, which are downregulated in both knee and hip OA, are associated with pathways such as HIF-1 and JAK-STAT, which modulate apoptotic signaling and transcriptional regulation. These miRNAs also interact with ceRNAs such as circ_0000254 and SPACA6P-AS, impacting proteins like STAT3, MCL1, and TRAF6. A drug interaction analysis identified 47 potential treatments, including Resveratrol and Acetaminophen, suggesting new therapeutic possibilities for OA management. This study not only highlights the role of miRNAs like hsa-miR-1303 and hsa-miR-125 in OA but also opens avenues for miRNA-based therapeutic development. Full article