SOUTHERN JOURNAL OF SCIENCES

It is investigated the effect of synthesized organic compounds of 6-hydroxy-2,2,4-trimethyl-1,2- dihydroquinoline, its derivatives, and hydrogenated analogs. These compounds affected the height of seedlings when they were used for pre-sowing seed treatment of the following ornamental plants: annual ornamental grass – scarlet sage (Salvia splendens) and woody plant – yellow rhododendron (Rhododendron luteum). Prior to the sprouting process, the seeds of Rh. luteum and S. splendens were soaked in water solutions of compounds with concentrations of 0.01%, 0.05%, and 0.1% for 18 hours. Dihydro- and tetrahydroquinolines with a concentration of 0.05% proved to be the most effective for both plants. For Rhododendron luteum, the compounds of 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline, its derivatives, and hydrogenated analogs with a concentration of 0.1% proved to be the most effective. Dihydroquinolines at concentrations of 0.05 and 0.1% proved to have the strongest effect when applied to the studied perennial woody plant (Rhododendron luteum). Dihydroquinoline at the concentration of 0.05% also proved to be effective when applied to the annual grass (Salvia splendens). For annual S. splendens, tetrahydroquinoline at concentrations of 0.01 and 0.05% appeared to be the most effective. The pre-sowing seed treatment of grass Salvia splendens and woody plant Rhododendron luteum with the studied compounds demonstrated that their effect on the height of the seedlings is species-specific. The pre-sowing seed treatment of Rh. luteum and S. splendens allows increasing the height of the seedlings by 3-61 % and 17-25 %, respectively. It is suggested using the compounds of 6-hydroxy-2,2,4- trimethyl-1,2-dihydroquinoline, its derivatives, and hydrogenated analogs as effective growth stimulators for ornamental grasses and woody plants.

Background: A crucial aspect of electrochemical enzymatic biosensor development is the immobilization of the enzymes, as it directly influences the sensitivity of the bioelectrode. Among the different methods used to incorporate enzymes on the surface of the transducers, layer-by-layer (LbL) self-assembly based on electrostatic interaction with polyelectrolytes of opposite charge stands out due to its simplicity and reproducibility. Aims: The aim of the work was to develop an electrochemical glucose biosensor by LbL assembly of a new functionalized chitosan polycation and the enzyme glucose oxidase (GOx). Methods: Chitosan was chemically functionalized with glucose by the Maillard reaction. The resulting polycation, named G-Chit, is soluble in the medium compatible with the enzyme. The bioelectrode was obtained by alternating adsorption of G-Chit and GOx onto carbon paste electrodes. By selecting the number of bilayer of G-Chit/GOX, the enzyme concentration, and the pH, the electroanalytical performance of the biosensor was optimized. The electrochemical responses were characterized by cyclic voltammetry and chronoamperometry. Results: Under optimized experimental conditions, the biosensor exhibited a sensitivity of (0.81 ± 0.03) µA mM-1 in a glucose concentration range of (0.18 to 1.75) mM. Discussion: Results indicated that catalytic response increases both with the number of G-Chit/GOx bilayers and the enzyme concentration, obtaining the best responses for 3 bilayers and 2 mg mL-1, respectively, while the optimum working pH value was 7.0. Conclusions: The analytical response of the biosensor was tested in milk samples with negligible matrix effects, suggesting a potential application in other dairy products. Results show that G-Chit appears promising for the immobilization of enzymes.

Background: Background: Vitamin D plays an essential role in bone health and overall physiological function, and its deficiency is common in children and adolescents with β-thalassemia major (βTM). Iron overload, as reflected by elevated ferritin, may further influence vitamin D status. Aim: This study aimed to evaluate serum vitamin D levels in βTM patients and determine their association with ferritin levels. Methods: A total of 40 βTM patients and 20 age-matched healthy controls (aged 4–25 years) were enrolled between October 2024 and February 2025. Serum vitamin D, calcium, ferritin, and hemoglobin were measured. Statistical analysis, including correlation and logistic regression, was performed using SPSS v.26 to identify predictors of vitamin D deficiency. Results: Vitamin D deficiency was highly prevalent among βTM patients (70%) compared with controls. Patients showed significantly lower vitamin D levels (17.32±1.56) than controls (25.34±1.76). Vitamin D levels were positively correlated with age (r = 0.788), calcium (r = 0.772), and hemoglobin (r = 0.771), and negatively correlated with ferritin (r = −0.517). Logistic regression demonstrated that ferritin >1000 ng/mL strongly predicted vitamin D deficiency (OR = 17.875; 95% CI: 3.258–98.074; p = 0.001), while younger age ( < 10 years) also increased the odds of deficiency (OR = 5.200; p = 0.018). Discussion: D deficiency is a prevalent and intrinsic metabolic disturbance in β-thalassemia major, closely linked to chronic iron overload and elevated ferritin levels. This interplay disrupts hepatic vitamin D hydroxylation, induces inflammation, and contributes to endocrine and skeletal complications, highlighting ferritin as a key predictor of deficiency in these patients. Conclusion: Vitamin D deficiency is highly prevalent in βTM and is strongly associated with elevated ferritin levels, suggesting that iron overload is a significant predictor. Integrating vitamin D assessment into routine monitoring may support better management of disease-related metabolic disturbances in patients with βTM.