Solvent and substitution effects on the UV/Vis spectroscopic and fluorescence behaviour of seven synthesized 3-substituted 4-hydroxycoumarin derivatives were tested. The tested compounds were dissolved in ethyl acetate, acetonitrile, and dimethyl sulfoxide. Absorption and emission spectra were recorded in the range of 200–800 nm. All tested 4-hydroxycoumarin derivatives showed good absorption in a wide range of 200–550 nm, depending on the properties of the substituents on the benzene ring of the cinnamoyl moiety and the type of solvent. In comparison to the unsubstituted analogue, compounds with an electron-donating group exhibited bathochromically shifted UV/Vis absorption and emission spectra. The highest fluorescence quantum yield was observed for compounds with dimethylamino and acetamido groups as substituents at the benzene ring. Considering that both substitution and solvent affect the absorption and emission spectra of the tested compounds, it can be concluded that judiciously selecting these parameters can improve their absorption and fluorescence properties, making them suitable for various analytical uses.

Skin sensitization is a crucial endpoint in the safety assessment of chemicals, with the Direct Peptide Reactivity Assay (DPRA) emerging as a valuable in chemico method for evaluating a substance's sensitization potential. This review delves into the principles, applicability, and limitations of the DPRA within the context of the Adverse Outcome Pathway (AOP) framework for skin sensitization. We examine the DPRA'srole in addressing the molecular initiating event of skin sensitization, its integration into Integrated Approaches to Testing and Assessment (IATA), and its performance in predicting sensitizers. The review also highlights the challenges in testing certain categories of chemicals and the importance of considering the DPRA's results alongside other complementary methods. By providing a comprehensive overview of the DPRA, this review aims to inform researchers, regulators, and clinicians about its utility and limitations in the context of skin sensitization testing.

Objective. The aim of this study was to investigate students’ knowledge, attitudes and hesitancy regarding COVID-19 vaccination. Methods. A cross-sectional questionnaire-based survey was conducted among a total of 1282 medical students and 509 non-medical students at four public universities in Bosnia and Herzegovina: Tuzla, Sarajevo, Banja Luka, and Mostar. Results. A significantly higher rate of vaccination was observed in the group of medical students as well as a higher level of knowledge about vaccination in general and vaccines against the COVID-19 disease. Students who received the COVID-19 vaccine had a higher level of knowledge about vaccination in general and COVID-19 vaccines in particular compared to the non-vaccinated students in the medical and non-medical groups, respectively. Furthermore, vaccinated students, regardless of the course they are taking, showed generally stronger positive attitudes compared to non-vaccinated students, regarding the safety and effectiveness of the COVID-19 vaccine. Both groups of students believe that the rapid development of the vaccine is contributing to refusal or hesitancy to receive a vaccine against COVID-19. Social media/networks were the main sources of information about the COVID-19 vaccine. We did not find any contribution of social media to the reduced level of COVID-19 vaccine coverage. Conclusion. Education of students about the benefits of the COVID-19 vaccine will lead to its better acceptance as well as the development of more positive attitudes towards vaccination in general, especially having in mind that students are the future population of parents, who will make decisions about vaccinating their children.

Plant-derived products are frequently found as ingredients in cosmetics. However, the current data show non-neglectable skin sensitizing potential of these preparations suggesting an urgent need for data regarding their health safety profile. The aim of this study was to assess the skin sensitization potential of commercial essential oils by selected Lamiaceae species (Lavandula angustifolia, Melissa officinalis, Mentha longifolia, Thymus vulgaris, Salvia officinalis, and Rosmarinus officinalis) using a chemistry-based Direct Peptide Reactivity Assay (DPRA) in order to predict their potential allergic properties. In the DPRA assay, nucleophile-containing synthetic peptides (cysteine peptide and lysine peptide) were incubated with the test substance for 24 h. Depletion of the peptide in the reaction mixture was measured by high-pressure liquid chromatography (HPLC) using UV detection and the average peptide depletion data for cysteine and lysine was then calculated. Menthae longifoliae aetheroleum showed no or minimal reactivity with 4.48% cysteine depletion, Rosmarini aetheroleum and Salviae aetheroleum showed low reactivity with the 12.79% and 15.34% of cysteine depletion, respectively, while the other analyzed essential oils showed moderate reactivity with the cysteine depletion between 23.21 and 48.43%. According to DPRA predictive analysis, only Menthae longifoliae aetheroleum can be classified as negative, while all other essential oils may be classified as positive, thus having the potential to cause skin sensitization.