Selective adsorption of glucose towards itaconic acid on amorphous silica surfaces: Insights from density functional theory calculations

Elucidating the roles of electrolytes and hydrogen bonding in the dewetting dynamics of the tear film

This study explores the impact of electrostatic interactions and hydrogen bonding on tear film stability, a crucial factor for ocular surface health. While mucosal and meibomian layers have been extensively studied, the role of electrolytes in the aqueous phase remains unclear. Dry eye syndrome, characterized by insufficient tear quantity or quality, is associated with hyperosmolality, making electrolyte composition an important factor that might impact tear stability. Using a model buffer solution on a silica glass dome, we simulated physiologically relevant tear film conditions. Sodium chloride alone induced premature dewetting through salt crystal nucleation. In contrast, trace amounts of solutes with hydroxyl groups (sodium phosphate dibasic, potassium phosphate monobasic, and glucose) exhibited intriguing phenomena: quasi-stable films, solutal Marangoni-driven fluid influx increasing film thickness, and viscous fingering due to Saffman-Taylor instability. These observations are rationalized by the association of salt solutions with increased surface tension and the propensity of hydroxyl-group-containing solutes to engage in significant hydrogen bonding, altering local viscosity. This creates a viscosity contrast between the bulk buffer solution and the film region. Moreover, these solutes shield the glass dome, counteracting sodium chloride crystallization. These insights not only advance our understanding of tear film mechanics but also pave the way for predictive diagnostics in dry eye syndrome, offering a robust platform for personalized medical interventions based on individual tear film composition.

ORNIDAZOL-BASED APPLICATION SORBENT WITH NANO SILICA AND ITS ANTIMICROBIAL ACTIVITY

OBJECTIVE

The aim: To investigate the effect of application sorbent based on ornidazole with nanosilicon in experiment and clinic.

PATIENTS AND METHODS

Materials and methods: In order to study the effectiveness of the Ornidasil application sorbent for the treatment of purulent wounds, we conducted an experimental study in rats. Also, we studied the effectiveness of the Ornidasil in the clinic for the treatment of patients with diabetic foot syndrome and to prevent the suppuration of postoperative wounds in patients with purulent peritonitis in toxic and terminal stages.

RESULTS

Results: The formation of active substance complexes with hydroxylated matrices is due to hydrogen bonds between the oxygen atom of the silanol group of the silica surface and the hydrogen atom of the alcohol group of the ornidazole molecule. This promotes the gradual release of ornidazole from the surface of such a matrix into the wound exudate. Thus, on day 13, 9 experimental rats of group I healed completely, 11 rats had a small wound surface, complete healing occurred on day 15. We also investigated the effectiveness Ornidasil in the clinic. In the comparison group, postoperative wound suppuration occurred in 6 patients (31.6%), and in the main group - in 3 patients (12.5%).

CONCLUSION

Conclusions: A study of the effectiveness Ornidasil in the complex treatment of Diabetic foot syndrome showed that in the experimental groups, wound healing occurred 1.6 -1.9 times faster. The use of polyurethane wound protector in combination with Ornidasil reduced the suppuration of postoperative wounds in patients of the main group by 2.5 times relative to patients in the comparison group.

Sustainable Downstream Separation of Itaconic Acid Using Carbon-Based Adsorbents

Separation of itaconic acid from aqueous solution has been explored using various carbon-based adsorbents obtained from the pyrolysis and KOH activation of coconut shell biomass. The best preparation conditions to obtain a tailored adsorbent for itaconic acid purification were identified via a Taguchi experimental design, where its adsorption properties were maximized. The best activated carbon was obtained via coconut shell pyrolysis at 750 °C for 4 h plus an activation with 0.1 KOH and a final treatment at 800 °C for 2 h. This adsorbent showed an adsorption capacity of 4.31 mmol/g at 20 °C and pH 3 with a surface area of 466 m2/g. Itaconic acid separation was exothermic and pH-dependent where electrostatic forces and hydrogen bonding were the main adsorption interactions. Calculated adsorption rate constants for itaconic acid adsorption were 0.44–1.20 h-1. Results of adsorbent characterization analysis indicated the presence of a crystallization of itaconic acid molecules onto the activated carbon surface where 3–4 molecules could interact to form the clusters. This organic acid was recovered from the adsorbent surface via desorption with water or ethanol, thus facilitating its final purification. The best activated carbon obtained in this study is a promising alternative to perform sustainable and energy-efficient downstream separation and purification of itaconic acid produced via fermentation.