Trakia University

Nanotechnology has emerged as a promising option in combating the worsening situation with antibiotic resistance. We studied the antimicrobial effectiveness of four types of green synthesized zinc oxide nanoparticles (ZnO-NPs), obtained via Pluronic-assisted co-precipitation by lavender and thyme essential oils and their praseodymium-doped variants. Resazurin Microtiter Assay was applied to a panel of Gram-positive and Gram-negative bacteria from Risk 1 and 2 groups and the ESKAPE group. In relation to the pro-oxidative features of the ZnO-NPs, the production of superoxide dismutase (SOD) and catalase (CAT) in the tested microorganisms was also investigated, as these enzymes are important participants in the antioxidant defense of the bacterial cell and are considered virulence factors. We hypothesized that the sensitivity of microorganisms to the action of ZnO-NPs is related to their innate levels of antioxidant enzyme activity. The results showed that all types of studied ZnO-NPs had an antibacterial effect against the entire panel of tested strains, but with different potencies. The strongest effect was found for Arthrobacter nicotianae, Oerskovia paurometabola, Bacillus subtilis, and Escherichia coli. Less inhibition was observed for bacteria from Risk group 2 maybe due to their better antioxidant protection, especially for Pseudomonas aeruginosa. Praseodymium doping contributed to enhancing the bactericidal effect. A correlation between susceptibility of bacteria to ZnO-NPs and their antioxidant enzyme activity was observed.

Introduction . Contemporary research in second or foreign language (L2) acquisition integrates cognitive, affective, and sociocultural factors. However, variability in findings arises from methodological heterogeneity and differences in learner age. Aim . The present study aimed to systematise empirical data on the influence of working memory (WM), executive functions (EF), motivation, emotional intelligence, and anxiety on L2 acquisition success across different age groups, and to identify moderators related to task type and learning context. Methodology and research methods . In accordance with PRISMA guidelines, a systematic review and meta-analysis of studies published from 2000 to September 2025 was conducted using the Web of Science, Scopus, PsycINFO, and Google Scholar databases. The inclusion criterion was the presence of a quantitative assessment of the relationship between at least one specified psycholinguistic factor and L2 performance. Random-effects models (REML), heterogeneity assessments (Q, τ², I²), Egger’s test for bias detection, and the trim-and-fill method were applied. Age, type of language task, and context (ESL/EFL/language environment) were included in the moderator analysis. Results . Out of 1,246 publications, 38 studies met the criteria. Strong correlations were found between L2 success and WM (r ≈ 0.54) and EF (d ≈ 0.46), as well as positive associations with motivation (r ≈ 0.32) and emotional intelligence (r ≈ 0.29). A negative correlation was observed with anxiety (r ≈ -0.25). These effects were more pronounced for lexical and reading tasks, in English as a Second Language (ESL) and language immersion contexts, and among young adults. For learners over 60, significant but more variable improvements were noted. Scientific novelty . Subject-specific and age-dependent mechanisms linking WM/EF to L2 outcomes have been identified. Methodological moderators related to research design have been quantitatively assessed for the first time. Practical significance . The results underscore the necessity of developing age- and context-specific methodologies that integrate a focus on form with the enhancement of EF/WM and anxiety regulation, utilising adaptive technologies – particularly for teaching older age groups.

Purpose: Peripheral Arterial Occlusive Disease (PAOD) is a vascular disease associated with high morbidity and mortality worldwide. The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism (rs4340) has been suggested as a potential risk factor for PAOD. This study aimed to examine the association of the ACE I/D polymorphism and PAOD risk in Bulgarian patients. Materials/Methods: This case-control study included 85 patients with PAOD and 394 controls. Genomic DNA was isolated from peripheral blood, and ACE genotyping was performed using classical end-point polymerase chain reaction. Results: ACE genotype frequencies were similar between PAOD patients (DD: 0.317; ID: 0.459; II:0.224) and controls (DD: 0.345; ID: 0.495; II: 0.160; p=0.368), as well as the allelic frequencies (p=0.274). Further analysis based on the clinical manifestation of the disease did not reveal a significant association with the ACE I/D polymorphism. However, a tendency for a higher frequency of the DD-genotype was observed among cases with arterial hypertension (0.348 vs. 0.188) or with atrophic changes (0.412 vs. 0.294), compared to patients without these conditions. Conclusion: There was no significant association between the ACE I/D polymorphism and the development of PAOD in the Bulgarian population. However, carrying the DD-genotype might contribute to the clinical characteristics of PAOD.

Sour milk, or "set yogurt" as defined by European terminology, is the most popular fermented dairy product in the region and has enjoyed growing global popularity over time. Access to international markets requires effective product protection, which can be achieved through the use of bioprotective probiotic cultures. This study aimed to investigate whether the addition of bioprotective cultures induces any changes in the qualitative properties of set yogurt initially inoculated with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The research material consisted of set yogurt samples supplemented with three different bioprotective cultures, along with a reference control. The study evaluated pH, fatty acid profiles, microbiological analyses and sensory characteristics, assessed by two independent sensory panels. The sensory attributes analyzed included appearance, aroma, consistency, spoon consistency, mouthfeel, taste/acidity, and aftertaste. Statistical analysis of the results demonstrated that the addition of bioprotective cultures did not significantly affect the qualitative properties of set yogurt during storage period.

This paper explores the transformation of the educational process under the influence of Generative Artificial Intelligence (AI) through a comparative analysis between high school students in the International Baccalaureate (IB) programmes and university students in technical and economic specialties at Trak University. A mixed-methods research design was employed, incorporating qualitative reflection through essays and a quantitative and qualitative survey: The results reveal that both groups perceive Al as a "cognitive partner," albeit with a different focus high school students use it for conceptual understanding, while university students utilise it for professional optimisation. The study identifies a critical need for developing "Al literacy and an ethical framework to prevent the risk of cognitive atrophy by shifting the focus from the final product to the intellectual process. The article addresses the potential of Al for personalised learning and automation, while simultaneously analysing risks such as technological dependence, lack of human emotional connection, data privacy concerns, and the impact on young brain development. It also emphasises the importance of "Prompt Engineering as a new foundational skill in the modern digital era.