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28 pages, 1639 KB  
Article
A Generative AI-Based Framework for Proactive Quality Assurance and Auditing
by Galina Ilieva, Tania Yankova, Vera Hadzhieva and Yuliy Iliev
Appl. Sci. 2026, 16(9), 4237; https://doi.org/10.3390/app16094237 (registering DOI) - 26 Apr 2026
Abstract
Generative artificial intelligence (AI) is increasingly used to support decision-making in manufacturing quality assurance (QA), but its adoption raises concerns regarding governance, traceability, and auditability. This paper proposes a proactive framework that integrates generative AI into quality management and auditing while preserving standards [...] Read more.
Generative artificial intelligence (AI) is increasingly used to support decision-making in manufacturing quality assurance (QA), but its adoption raises concerns regarding governance, traceability, and auditability. This paper proposes a proactive framework that integrates generative AI into quality management and auditing while preserving standards alignment and human oversight. The framework structures quality activities across supplier, in-process, and post-market domains and across three hierarchical levels—product, process, and operation—to link quality outcomes with documentary evidence requirements. A proof-of-concept (PoC) study in electronics manufacturing focused on New Product Introduction (NPI) planning and compared two parallel workflows: an expert QA team and a generative AI-assisted chatbot workflow. Within a fixed time window, both workflows produced an aligned Process Failure Mode and Effects Analysis (PFMEA), Control Plan, supplier Production Part Approval Process (PPAP) request package, and internal audit evidence pack. Three independent experts evaluated the integrated deliverable package using five indices covering documentation quality and audit readiness, detection and containment logic, process capability and stability, governance and provenance safeguards, and execution (time) efficiency. Compared with the expert package, the generative AI–assisted workflow produced more traceable, governance-rich documentation (ownership, versioning, clause-to-evidence links) and reduced manual audit-evidence consolidation, supporting quality planning and change-control readiness. Full article
38 pages, 2267 KB  
Article
Sustainable Parking Allocation for Smart Cities Using Digital Twin and Agentic Optimization
by Hamed Nozari and Zornitsa Yordanova
Future Transp. 2026, 6(3), 95; https://doi.org/10.3390/futuretransp6030095 (registering DOI) - 26 Apr 2026
Abstract
The rapid increase in the number of cars in large cities has made efficient parking management one of the major challenges of urban transportation systems. The present study aims to develop a smart framework for sustainable allocation of parking spaces in urban environments, [...] Read more.
The rapid increase in the number of cars in large cities has made efficient parking management one of the major challenges of urban transportation systems. The present study aims to develop a smart framework for sustainable allocation of parking spaces in urban environments, and presents an integrated approach based on digital twin and multi-objective optimization. In this framework, a digital model of the urban parking system is created that is able to analyze real and simulated data related to parking demand, space occupancy status, and traffic flow and support optimal allocation decisions. The results of the analysis show that using the proposed framework can reduce parking search time by an average of 28%, make the distribution of parking use more balanced, and consequently reduce the amount of pollutant emissions from vehicle movement by about 17%. Also, sensitivity and scalability analyses show that the proposed model also has stable and reliable performance in large urban networks. These results indicate that the proposed framework can be used as an effective tool for developing sustainable parking management systems in smart cities. Full article
(This article belongs to the Special Issue Parking Allocation for Smart Cities)
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14 pages, 1201 KB  
Article
Testing Climatic Stability–Endemism Relationships Using Western Balkan Endemic Beetles’ Localities and Paleoclimate Reconstructions
by Desislava Stoianova and Ivan Tomov
Ecologies 2026, 7(2), 38; https://doi.org/10.3390/ecologies7020038 (registering DOI) - 26 Apr 2026
Abstract
An association between long-term climatic stability and endemism has been suggested, but it has been tested in plants and vertebrates rather than invertebrates. Using high-resolution paleoclimate reconstructions (CHELSA-TraCE21k; 21,000 BP–present), we tested whether non-cave localities of endemic beetles in the western Balkans are [...] Read more.
An association between long-term climatic stability and endemism has been suggested, but it has been tested in plants and vertebrates rather than invertebrates. Using high-resolution paleoclimate reconstructions (CHELSA-TraCE21k; 21,000 BP–present), we tested whether non-cave localities of endemic beetles in the western Balkans are non-randomly associated with local climatic stability. For four bioclimatic variables, we quantified temporal variability using three metrics (SD, range, detrended SD) and defined stability islands as cells in the most stable quartile relative to their neighbourhood at three spatial scales (3 × 3, 5 × 5, 9 × 9). We tested whether 578 endemic-locality cells were enriched in stability islands, against elevation-matched null models. Annual mean temperature produced the highest raw frequency of endemic localities in stability islands, but this pattern was not significant after elevation control. In contrast, endemic localities showed a modest but consistent enrichment in annual precipitation stability islands (observed 9.7–10.7% vs. null 7.3–8.5%; p = 0.01–0.03) across neighbourhood sizes. At the 3 × 3 scale, 60 endemic localities fell within precipitation-stability islands; of them, 20 were outside current protected areas—indicating conservation gaps where minor boundary revisions could enable protection of endemic beetles’ habitats in precipitation-stable sites. Full article
(This article belongs to the Special Issue Advances in Community Ecology: Interactions, Dynamics, and Diversity)
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26 pages, 1768 KB  
Article
High-Accuracy Characterization of a Single Thin Film on a Substrate from One Transmittance Spectrum by an Advanced Envelope Method Addressing Voids, Tail Electron Transitions, and Deep-Level Electron Transitions in a-Si Films
by Dorian Minkov, George Angelov, Dimitar Nikolov, Rostislav Rusev, Manuel Ballester, Susana Fernandez and Emilio Marquez
Nanomaterials 2026, 16(9), 522; https://doi.org/10.3390/nano16090522 (registering DOI) - 26 Apr 2026
Abstract
In most amorphous materials, the concentration of Urbach tail states is larger than the concentration of dangling bond states. However, absorption accounting for the Urbach tail while disregarding the dangling bonds is commonly used or derived by spectroscopic characterizations of amorphous films from [...] Read more.
In most amorphous materials, the concentration of Urbach tail states is larger than the concentration of dangling bond states. However, absorption accounting for the Urbach tail while disregarding the dangling bonds is commonly used or derived by spectroscopic characterizations of amorphous films from a single spectrum, mostly due to the insufficient accuracy of such characterizations. This paper proposes an advanced envelope method (AEM) for transmittance spectrum T(λ), aiming to resolve this problem. The novelties in AEM are: improved preprocessing of T(λ), extending the envelopes deeper into the region of strong absorption (RSA), enhanced determination of the refractive index n(λ) in the region of weak absorption, optimization of both n(λ) and the extinction coefficient k(λ) in RSA, as well as analysis of the types of electron transitions and calculation of their energy gaps. Three single magnetron sputtered a-Si films deposited on glass substrates are characterized by AEM, and three other relevant methods that disregard deep-levels. The best accuracy is achieved when these films are characterized by AEM. It is demonstrated that the absorption coefficient α(λ) of each of these films distinguishes electron transitions via dangling bond states from those via tails states, and the DOS corresponds to the Mott–Davis model of amorphous materials. Full article
(This article belongs to the Section Theory and Simulation of Nanostructures)
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41 pages, 647 KB  
Article
Educational Factor of Human Capital: Key Point for Sustainable Development and Strategic Competitiveness in Kazakhstan’s Metallurgical Enterprise
by Sergey Polevoy, Mariana Petrova and Assiya Atabayeva
Sustainability 2026, 18(9), 4287; https://doi.org/10.3390/su18094287 (registering DOI) - 26 Apr 2026
Abstract
This research analyzes “educational” factors influencing the human capital of a labor collective from Karaganda Metallurgical Plant from the perspective of the enterprise’s potential qualitative development. The purpose of this article is to consider the importance of educational factors in understanding the concept [...] Read more.
This research analyzes “educational” factors influencing the human capital of a labor collective from Karaganda Metallurgical Plant from the perspective of the enterprise’s potential qualitative development. The purpose of this article is to consider the importance of educational factors in understanding the concept of “human capital” by employees of the enterprise. An additional goal is the description of various factors, influencing satisfaction with the educational component. The authors tested the following hypothesis: the factor of education directly affects employees’ satisfaction with the level of human capital development at the enterprise. The research results are based on a personnel survey about level of educational satisfaction, its quality and its accessibility. The main analysis tool to verify the stated hypothesis was structural modeling in the Smart PLS. The analysis of the research results revealed dissatisfaction from a significant portion of the respondents with the approaches to vocational education established at the enterprise, despite the fact that a high importance of the educational aspect in human capital formation was confirmed by the respondents during the hypothesis testing procedure for same survey’s results. The identified problems were explained by a discrepancy between the manufacturing tasks and the skills and knowledge acquired by the respondents. This research has the potential for development within the framework of company policy analysis in the field of education. Full article
36 pages, 9299 KB  
Article
Revision of the Genus Cyanoboletus (Boletaceae) in the Mediterranean Basin with Notes on Arsenic Hyperaccumulation
by Alona Yu. Biketova, Isaac Garrido-Benavent, Vasco Fachada, Giampaolo Simonini, Matteo Gelardi, Boris Assyov, Elias Polemis, Antoni Conca, Roseina Woods, Georgios I. Zervakis, Jan Borovička and Andrea C. Rinaldi
J. Fungi 2026, 12(5), 315; https://doi.org/10.3390/jof12050315 (registering DOI) - 25 Apr 2026
Abstract
This study revises the genus Cyanoboletus (Boletaceae) in the Mediterranean Basin, integrating single-locus and multi-locus phylogenetic analyses (ITS, LSU, tef1-α, and rpb2), morphological characterisation, ecology, and arsenic accumulation in basidiomes. Morphological descriptions (including a new form, Cyanoboletus mediterraneensis f. [...] Read more.
This study revises the genus Cyanoboletus (Boletaceae) in the Mediterranean Basin, integrating single-locus and multi-locus phylogenetic analyses (ITS, LSU, tef1-α, and rpb2), morphological characterisation, ecology, and arsenic accumulation in basidiomes. Morphological descriptions (including a new form, Cyanoboletus mediterraneensis f. pallidus), comprehensive sampling, type studies, biogeography, macro- and microphotographs, an identification key, and a historical overview of the nomenclatural issues surrounding C. pulverulentus, C. poikilochromus, and C. mediterraneensis are given. An epitype collection is designated for C. pulverulentus. A new method to measure spore suprahilar depression has been proposed, which allowed more clear morphological separation between C. mediterraneensis and C. pulverulentus. This method may prove useful for species delimitation in other fungal groups that have asymmetric basidiospores. Additionally, we generated a new ITS sequence of the C. sinopulverulentus holotype and inferred its conspecificity with the later described C. flavocontextus. Furthermore, notes on the taxonomy of Boletus gabretae are presented, and its placement in the genus Neoboletus is suggested. Cyanoboletus is confirmed as a strongly supported generic clade encompassing 21 monophyletic species-level clades, 14 of which represent known species, and seven are undescribed taxa. The synonymy of Cupreoboletus with Cyanoboletus is also verified. This publication provides the tools to delimit Cyanoboletus species that have important conservation value, which can be used by conservationists, ecologists, and citizen scientists. It also highlights species-specific arsenic hyperaccumulation in C. pulverulentus, contributing to a better understanding of fungal metal uptake. Our study indicates that within Cyanoboletus, only C. pulverulentus demonstrates this characteristic and is the only known member of Boletales that possesses a high arsenic accumulation ability. Full article
(This article belongs to the Special Issue Fungal Diversity in Europe, 4th Edition)
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16 pages, 6778 KB  
Article
Regional Expression of Vimentin, S100, and Epithelial Membrane Antigen in the Human Medial Collateral Ligament: A Robust Two-Way Analysis of Variance
by Nikola Stamenov, Boycho Landzhov, Maria Piagkou, Ahmed Al-Sadek, Lyubomir Gaydarski, Kristina Petrova, Georgi Luchev, Julian Ananiev, Iva N. Dimitrova and Georgi P. Georgiev
J. Funct. Morphol. Kinesiol. 2026, 11(2), 173; https://doi.org/10.3390/jfmk11020173 (registering DOI) - 25 Apr 2026
Abstract
Background: The epiligament (EL) of the medial collateral ligament (MCL) has recently attracted increasing attention as a biologically active structure. Emerging evidence suggests that it may contribute to ligament healing by providing progenitor cells, vascular components, and signaling mediators. However, its cellular [...] Read more.
Background: The epiligament (EL) of the medial collateral ligament (MCL) has recently attracted increasing attention as a biologically active structure. Emerging evidence suggests that it may contribute to ligament healing by providing progenitor cells, vascular components, and signaling mediators. However, its cellular composition and possible regional variability remain insufficiently characterized. Aim: This study evaluated the expression of vimentin, S100 protein, and epithelial membrane antigen (EMA) to better characterize the EL compared with the ligament proper (LP). Methods: Twelve human MCLs obtained from twelve deceased donors were divided into proximal, middle, and distal segments. Thirty-six paraffin blocks were prepared, from which 180 sections were obtained and equally assigned for immunohistochemical staining of vimentin, S100 protein, and EMA (60 slides for each marker). Systematic quantification of seven to eight non-overlapping microscopic fields per slide generated 900 standardized observations for each investigated marker. This sampling strategy provided 150 measurements for each sub-region (EL and LP across the three anatomical segments). Immunoreactivity was quantified using ImageJ software. Statistical differences were analyzed using a robust two-way analysis of variance (ANOVA), while biological associations between markers were assessed using Spearman’s rank correlation analysis. Results: Vimentin and S100 expression were consistently higher in the EL than in the LP across all anatomical regions (p < 0.0001). The highest vimentin values were observed in the proximal region (median 17.34 vs. 10.14) and distal region (median 19.34 vs. 11.23), whereas S100 showed the greatest expression in the proximal (median 16.9 vs. 7.2) and distal regions (median 14.1 vs. 8.9). EMA expression was generally lower overall; however, it remained significantly higher in the EL than in the LP within the proximal (median 6.87 vs. 5.77) and middle regions (median 4.80 vs. 3.26). No significant difference was identified in the distal region. Spearman rank correlation analysis demonstrated significant positive associations among all investigated markers (p < 0.001), with the strongest relationship observed between vimentin and S100 protein (Spearman correlation coefficient = 0.430). Conclusions: The EL of the MCL is a structurally and biologically distinct component, characterized by significantly higher expressions of vimentin, S100, and EMA than the LP. The significant positive correlations observed among these markers support the concept that the EL functions as an integrated biological microenvironment with clear regional heterogeneity, particularly within the proximal and distal segments. Further studies are warranted to clarify the functional relevance of these findings and their potential implications for clinical management and ligament healing strategies. Full article
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16 pages, 36705 KB  
Article
From Adult Morphology to Developmental Hypothesis: Variation of the Adult Lateral Wrist Extensors—A Developmental Viewpoint
by Dimo S. Stoyanov, Tsvetomir E. Kachovski, Kamelia Bratoeva, Anton B. Tonchev, Emil G. Kovachev and Stoyan P. Pavlov
J. Funct. Morphol. Kinesiol. 2026, 11(2), 172; https://doi.org/10.3390/jfmk11020172 - 24 Apr 2026
Abstract
Background: Anatomical variations are inevitable part of studying the human body. Very often, muscles of the limbs may show atypical attachments, extra or fewer muscle bellies. These variations are likely rooted in limb development. Our goal was to thoroughly study and describe the [...] Read more.
Background: Anatomical variations are inevitable part of studying the human body. Very often, muscles of the limbs may show atypical attachments, extra or fewer muscle bellies. These variations are likely rooted in limb development. Our goal was to thoroughly study and describe the variations in the lateral wrist extensors. Our initial goal was to attempt to explain the developmental processes that occur before the formation of these variations, with a focus on the interconnecting tendons. Methods: We used a standard dissection technique, paying extra attention to the space between the two radial wrist extensors to properly visualize interconnecting tendons. Taking advantage of the chi square test, we compared the observed vs the expected random distribution of interconnecting tendons. Results: In this article, we systematically studied the variations in the interconnecting tendons of the lateral carpal extensors in 58 upper limbs of our cadaver donors used for the education of medical students. The main variation we found is interconnecting tendons between the extensor carpi radialis longus and extensor carpi radialis brevis. The insertion and origin of the interconnecting tendons were consistent: it either originates from the middle of the ECRB body and inserts medial to ECRL tendon or it originates from the ventral side ECRL and inserts ventral to the ECRB tendon. We supplemented them with two dissections of fetal upper limbs (at GW 12 and GW 17). Statistical analysis of the distribution of single vs double interconnecting tendons suggests that they are dependent events, consistent with literature data. Conclusions: Based on our observations and the literature, we propose that oblique muscle division and a mismatch between the muscle fission plane and the initial distal tendon fission plane may result in the observed phenotype. We also suggest that the origin of the extra numerary tenons form ECRL body may play a role when choosing which one to mobilize for tendon transfer. Full article
(This article belongs to the Section Functional Anatomy and Musculoskeletal System)
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10 pages, 4758 KB  
Case Report
A Case of Primary EGFR T790M Mutation in Treatment-Naïve Advanced NSCLC: Clinical and Molecular Implications
by George Dimitrov, Elitsa Kraevska, Vladislav Nankov, Victoria Hlebarova and Savelina Popovska
Curr. Oncol. 2026, 33(5), 244; https://doi.org/10.3390/curroncol33050244 - 24 Apr 2026
Abstract
Background: De novo (pretreatment) EGFR T790M mutation is a rare molecular finding in non-small cell lung cancer (NSCLC) and has historically been associated with primary resistance to first- and second-generation EGFR tyrosine kinase inhibitors (TKIs). Evidence guiding optimal first-line management in this subgroup, [...] Read more.
Background: De novo (pretreatment) EGFR T790M mutation is a rare molecular finding in non-small cell lung cancer (NSCLC) and has historically been associated with primary resistance to first- and second-generation EGFR tyrosine kinase inhibitors (TKIs). Evidence guiding optimal first-line management in this subgroup, particularly in elderly patients, remains limited. Case Presentation: We report a case of an elderly patient with treatment-naïve advanced non-squamous NSCLC harboring a concurrent EGFR exon 19 deletion and de novo EGFR T790M mutation. Given the patient’s age, significant cardiopulmonary comorbidities, and absence of rapidly progressive disease, a multidisciplinary tumor board recommended first-line osimertinib monotherapy. Treatment was well tolerated, with rapid improvement in performance status and no clinically significant adverse events. Serial contrast-enhanced CT restaging demonstrated RECIST 1.1–defined stable disease, without development of new visceral, nodal, cerebral, or osseous metastases. The patient remains on continuous osimertinib therapy with durable disease control at the time of manuscript preparation. Conclusion: Primary EGFR T790M–positive NSCLC can achieve durable disease control with first-line osimertinib, even in advanced age. While combination strategies with chemotherapy may improve survival outcomes in selected patients, treatment decisions in elderly individuals must carefully balance efficacy, toxicity, and quality of life. Chronological age alone should not discourage active targeted treatment when guided by molecular profiling and comprehensive clinical assessment. Full article
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21 pages, 401 KB  
Article
The Welfare of Refugee Children in Bulgarian Society in the Context of State Policies and Public Attitudes
by Albena Ilieva Nakova and Valentina Georgieva Milenkova
Societies 2026, 16(5), 141; https://doi.org/10.3390/soc16050141 - 24 Apr 2026
Abstract
In recent years, the escalation of international and internal conflicts in the Middle East and North Africa and Bulgaria’s geographical location, which places it on the route of those seeking protection from these regions in Europe, has led to a significant increase in [...] Read more.
In recent years, the escalation of international and internal conflicts in the Middle East and North Africa and Bulgaria’s geographical location, which places it on the route of those seeking protection from these regions in Europe, has led to a significant increase in the number of refugee children arriving in Bulgaria. According to Eurostat data, Bulgaria ranks fourth in terms of the number of unaccompanied refugee children in the European Union. In this article, the possibilities for achieving the welfare of refugee children and their successful integration into society are considered as a result of the intersection of two main trends—state legislation and public policies aimed at guaranteeing the best interests of refugee children, and public opinion about refugee children, which, in some cases, cause the failure of positive state measures and policies. The data on public attitudes towards refugee children used here are the result of an empirical study conducted in 2021 by the authors of this article. The results show that while state legislation and public policies are evolving towards ensuring the best interests of the child, the same cannot be said for public attitudes and the distance that the local population demonstrates towards refugee children. Full article
14 pages, 534 KB  
Article
Improvements to the Modified Anderson–Björck (modAB) Root-Finding Algorithm
by Nedelcho Ganchovski, Oscar Smith, Christopher Rackauckas, Lachezar Tomov and Alexander Traykov
Algorithms 2026, 19(5), 332; https://doi.org/10.3390/a19050332 - 24 Apr 2026
Abstract
The Modified Anderson–Björck method is a new, robust, and efficient bracketing root-finding algorithm. It combines bisection with the Anderson–Björk method to achieve both fast performance and worst-case optimality. It relies on linearity check criteria for switching methods and uses Anderson–Björk corrections to overcome [...] Read more.
The Modified Anderson–Björck method is a new, robust, and efficient bracketing root-finding algorithm. It combines bisection with the Anderson–Björk method to achieve both fast performance and worst-case optimality. It relies on linearity check criteria for switching methods and uses Anderson–Björk corrections to overcome the fixed endpoint issue of false-position. Initial benchmarks of this method have shown certain performance advantages compared to other methods, such as Ridders, Brent and ITP. In this paper, we propose further improvements to this method and perform some additional analysis and benchmarks of its behavior and performance. Full article
12 pages, 2592 KB  
Article
Cerium-Doped ZnO Thin Films for Photocatalysts
by Pavlina Bancheva-Koleva, Stephan Kozhukharov, Christian Girginov, Ivo Banchev, Plamen Petkov, Tamara Petkova and Georgi Avdeev
Materials 2026, 19(9), 1739; https://doi.org/10.3390/ma19091739 - 24 Apr 2026
Abstract
In this work, Ce-doped ZnO thin films at various contents of cerium were deposited on glass substrates by thermal vacuum evaporation to study the influence of Ce concentration on their optical, structural, morphological, and photocatalytic behavior. Pure ZnO and Ce-doped ZnO films doped [...] Read more.
In this work, Ce-doped ZnO thin films at various contents of cerium were deposited on glass substrates by thermal vacuum evaporation to study the influence of Ce concentration on their optical, structural, morphological, and photocatalytic behavior. Pure ZnO and Ce-doped ZnO films doped with 2% and 5% Ce were characterized by SEM, XRD, AFM, UV–VIS spectroscopy, and ellipsometry. The XRD analysis confirmed that all the films retained the hexagonal wurtzite structure, while Ce incorporation induced lattice strain and reduced crystallite size, particularly at higher doping levels. SEM and AFM studies showed that films with 2% Ce exhibited smaller grain size and lower roughness, whereas 5% Ce-doped films showed grain growth and increased roughness. Pure ZnO films displayed high transparency (>90%), whereas Ce incorporation caused a red shift in the absorption edge and narrowing of the optical band gap due to defect-related states and lattice distortion. Photocatalytic experiments revealed that Ce doping improved charge carrier separation and increased the number of oxygen vacancies. Among all samples, the 2% Ce-doped ZnO film demonstrated the highest photocatalytic efficiency. These findings highlight the importance of controlled Ce doping in tuning the microstructure, optical properties, and photocatalytic performance of ZnO thin films, making them suitable for environmental remediation and optoelectronic applications. Full article
17 pages, 3054 KB  
Article
Biomimetic Fibrin Matrix Modulates Early Human Follicular Growth Dynamics in a Bioengineered Artificial Ovary Derived from Cryopreserved Tissue: In Vitro Morphometric Assessment
by Mengyang Cao, Plamen Todorov, Cheng Pei, Gohar Rahimi, Christine Skala and Volodimir Isachenko
Int. J. Mol. Sci. 2026, 27(9), 3799; https://doi.org/10.3390/ijms27093799 - 24 Apr 2026
Abstract
Ovarian tissue cryopreservation is the primary fertility preservation strategy for prepubertal girls and patients requiring urgent gonadotoxic therapy. However, the risk of reintroducing malignant cells has prompted the development of safer alternatives, including follicle isolation followed by three-dimensional scaffold encapsulation for transplantation. Fibrin [...] Read more.
Ovarian tissue cryopreservation is the primary fertility preservation strategy for prepubertal girls and patients requiring urgent gonadotoxic therapy. However, the risk of reintroducing malignant cells has prompted the development of safer alternatives, including follicle isolation followed by three-dimensional scaffold encapsulation for transplantation. Fibrin is a promising biomaterial for bioengineered ovary construction, although its ability to support early human follicle maintenance remains unclear. Follicles isolated from cryopreserved ovarian tissues of six patients were encapsulated within fibrin scaffolds of graded concentrations (high, medium, low). After 7 days of in vitro culture, follicle survival and diameter change were quantified. A total of 282 follicles (45.4 ± 10.1 µm) were embedded into fibrin scaffolds. After culture, 237 viable follicles were detected, yielding an overall survival of 84%. Follicle diameter increased to 58.8 ± 12.0 µm. Follicle survival rates were comparable across groups, while mean follicle diameter was 56.3 ± 12.5 µm (high), 61.9 ± 13.4 µm (medium), and 57.4 ± 9.3 µm (low). Follicles cultured in medium-concentration fibrin demonstrated significantly larger diameters compared with both high and low groups (p < 0.05), with no difference between high and low groups. Fibrin-based bioprosthetic ovary scaffolds support short-term in vitro maintenance of isolated human follicles, preserving spherical morphology and granulosa cell layer integrity. Medium-concentration fibrin was associated with greater follicle diameter expansion compared with higher and lower concentrations, indicating that scaffold composition influences early morphometric changes during in vitro follicle culture. Full article
(This article belongs to the Section Molecular Biology)
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13 pages, 1832 KB  
Article
Evaluating Radon Adsorption Characteristics of Adsorbents by Parallel Exposures at Different Temperatures
by Dobromir Pressyanov, Momchil Momchilov and Peter A. Georgiev
Appl. Sci. 2026, 16(9), 4183; https://doi.org/10.3390/app16094183 - 24 Apr 2026
Abstract
Reliable determination of radon adsorption properties in candidate adsorbents is essential for developing highly sensitive methods capable of measuring low 222Rn activity concentrations in air. Such measurements are increasingly important in environmental monitoring, climate research, and low-background experiments. Conventional approaches for determining [...] Read more.
Reliable determination of radon adsorption properties in candidate adsorbents is essential for developing highly sensitive methods capable of measuring low 222Rn activity concentrations in air. Such measurements are increasingly important in environmental monitoring, climate research, and low-background experiments. Conventional approaches for determining the adsorption coefficient and heat of adsorption are labor- and time-intensive, limiting their suitability for comparative studies under identical conditions. Here, a recently proposed method is applied for the first time in a systematic comparative study. The approach couples solid-state nuclear track detectors (SSNTDs) with adsorbents that simultaneously act as radon collectors and alpha emitters, enabling fully parallel exposure and signal acquisition across multiple samples. Eight adsorbents—three activated carbon fabrics, two bulk activated carbons, and three synthetic zeolites—were evaluated simultaneously over a temperature range of 0–46.5 °C. Activated carbon fabrics exhibited the highest adsorption coefficients, with ACC-5092-10 reaching 11.8 ± 1.3 m3/kg at 20 °C. The heats of adsorption ranged from 24.8 ± 3.9 to 33.3 ± 5.0 kJ/mol, consistent with the literature values. For synthetic zeolites, the adsorption coefficient increased linearly with the Si:Al ratio. The influence of water content was further investigated for the five best-performing materials. The most hydrophobic material, zeolite SA-25 (Si:Al = 25), showed only a 25% reduction in adsorption coefficient under saturated humidity, whereas activated carbons exhibited strong suppression. These results demonstrate the practicality, sensitivity, and efficiency of the SSNTD–adsorbent method for comparative radon adsorption studies. Full article
(This article belongs to the Section Energy Science and Technology)
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27 pages, 3363 KB  
Article
Machine Learning-Driven Comparative Analysis and Optimization of Cu-Ni-Si and Cu Low Alloys: From Data-Driven Interpretation to Inverse Design
by Mihail Kolev
Alloys 2026, 5(2), 9; https://doi.org/10.3390/alloys5020009 - 24 Apr 2026
Abstract
The development of high-performance copper alloys requires balancing mechanical strength and electrical conductivity, properties that are often inversely correlated due to competing strengthening mechanisms. This study presents a comparative machine learning analysis of Cu-Ni-Si and Cu low alloys using a curated dataset of [...] Read more.
The development of high-performance copper alloys requires balancing mechanical strength and electrical conductivity, properties that are often inversely correlated due to competing strengthening mechanisms. This study presents a comparative machine learning analysis of Cu-Ni-Si and Cu low alloys using a curated dataset of 1690 entries derived from the Gorsse et al. database, comprising 1507 samples with hardness measurements and 1685 samples with electrical conductivity data. Three ensemble-based regression algorithms, Random Forest, XGBoost, and Gradient Boosting, were trained to predict Vickers hardness (HV) and electrical conductivity (%IACS) from an augmented feature set encompassing alloy composition, thermomechanical processing parameters, missingness indicators, and physics-informed descriptors (valence electron concentration, atomic size mismatch, electronegativity difference, and Ni:Si atomic ratio). XGBoost achieved optimal performance for hardness prediction (R2 = 0.8554, RMSE = 29.90 HV), while Gradient Boosting performed best for electrical conductivity (R2 = 0.8400, RMSE = 5.96%IACS). Averaged tree-based feature-importance analysis identified valence electron concentration as the most influential predictor for hardness (39.9%), followed by aging temperature (11.2%), while Cu content dominated conductivity prediction (37.7%), followed by aging time (8.9%). Complementary SHAP analysis confirmed these trends while revealing directional relationships and nonlinear feature interaction effects. Composition-grouped cross-validation by unique alloy formula (K = 10) yielded substantially lower performance, with grouped CV R2 = 0.438 for hardness and 0.293 for conductivity, indicating that generalization to unseen alloy formulations remains limited. The models were further applied for practical tasks, including property prediction for new alloy compositions, processing parameter optimization via differential evolution with metallurgical constraints (achieving hardness up to 293.9 HV or conductivity up to 45.7%IACS for the same base composition, with prediction intervals reported), and inverse design to identify alloy formulations meeting specified target properties. This work demonstrates the potential of interpretable machine learning to support copper alloy development by enabling rapid computational screening of the compositional and processing parameter space, subject to the generalization limitations identified herein. Full article
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