Raman Spectroscopic Characterization of the Interlayer Structure of Na+-Montmorillonite Clay Modified by Ditetradecyl Dimethyl Ammonium Bromide

Nanocomposite alginate hydrogel loaded with propranolol hydrochloride kolliphor® based cerosomes as a repurposed platform for Methicillin-Resistant Staphylococcus aureus-(MRSA)-induced skin infection; in-vitro, ex-vivo, in-silico, and in-vivo evaluation

Nanocomposite alginate hydrogel containing Propranolol hydrochloride (PNL) cerosomes (CERs) was prepared as a repurposed remedy for topical skin Methicillin-Resistant Staphylococcus aureus (MRSA) infection. CERs were formed via an ethanol injection technique using different ceramides, Kolliphores® as a surfactant, and Didodecyldimethylammonium bromide (DDAB) as a positive charge inducer. CERs were optimized utilizing 13. 22 mixed-factorial design employing Design-Expert® software, the assessed responses were entrapment efficiency (EE%), particle size (PS), and zeta potential (ZP). The optimum CER, composed of 5 mg DDAB, ceramide VI, and Kolliphor® RH40 showed tubular vesicles with EE% of 92.91 ± 0.98%, PS of 388.75 ± 18.99 nm, PDI of 0.363 ± 0.01, and ZP of 30.36 ± 0.69 mV. Also, it remained stable for 90 days and manifested great mucoadhesive aspects. The optimum CER was incorporated into calcium alginate to prepare nanocomposite hydrogel. The ex-vivo evaluation illustrated that PNL was permeated in a more prolonged pattern from PNL-loaded CERs nanocomposite related to PNL-composite, optimum CER, and PNL solution. Confocal laser scanning microscopy revealed a perfect accumulation of fluorescein-labeled CERs in the skin. The in-silico investigation illustrated that the PNL was stable when mixed with other ingredients in the CERs and confirmed that PNL is a promising candidate for curing MRSA. Moreover, the PNL-loaded CERs nanocomposite revealed superiority over the PNL solution in inhibiting biofilm formation and eradication. The PNL-loaded CERs nanocomposite showed superiority over the PNL-composite for treating MRSA infection in the in-vivo mice model. Histopathological studies revealed the safety of the tested formulations. In conclusion, PNL-loaded CERs nanocomposite provided a promising, safe cure for MRSA bacterial skin infection.

Raman Spectroscopy Study of Structurally Uniform Hydrogenated Oligomers of α-Olefins

The expansion of the range of physico-chemical methods in the study of industrially significant α-olefin oligomers and polymers is of particular interest. In our article, we present a comparative Raman study of structurally uniform hydrogenated dimers, trimers, tetramers, and pentamers of 1-hexene and 1-octene, that are attractive as bases for freeze-resistant engine oils and lubricants. We found out that the joint monitoring of the disorder longitudinal acoustic mode (D-LAM) and symmetric C–C stretching modes allows the quantitative characterization of the number and length of alkyl chains (i.e., two structural characteristics), upon which the pour point and viscosity of the hydrocarbons depend, and to distinguish these compounds from both each other and linear alkanes. We demonstrated that the ratio of the contents of CH₂ and CH₃ groups in these hydrocarbons can be determined by using the intensities of the bands in the spectra, related to the asymmetric stretching vibrations of these groups. The density functional theory (DFT) calculations were applied to reveal the relations between the wavenumber and bandshape of the symmetric C–C stretching mode and a conformation arrangement of the 1-hexene and 1-octene dimers. We found that the branched double-chain conformation results in the splitting of the C–C mode into two components with the wavenumbers, which can be used as a measure of the length of branches. This conformation is preferable to the extended-chain conformation for hydrogenated 1-hexene and 1-octene dimers.

Technological applications of organo-montmorillonites in the removal of pyrimethanil from water: adsorption/desorption and flocculation studies

Pyrimethanil (2-aniline-4, 6-dimethylpyrimidine, PRM) is used in fruit packing plants to control fungal infections and diseases. The effluents greatly polluted with this fungicide, as a point source contamination, need to be technologically treated for their regeneration before they reach water bodies. This work evaluates the use of organo-montmorillonites, synthetized in our laboratory, for their application in adsorption and coagulation/flocculation processes for the removal of PRM from water. The adsorption-desorption performance of PRM in a raw montmorillonite (Mt) and several organo-montmorillonites (organo-Mt) obtained by different amounts and types of exchanged surfactants (octadecyltrimethylammonium (ODTMA) and didodecyldimethylammonium (DDAB) bromides and benzyltrimethylammonium chloride (BTMA)) was studied. The PRM adsorption on raw Mt was assigned mainly to an interlayer occupancy, while hydrophobic interactions between PRM and the surfactants in the exchanged samples increased PRM adsorption, which was correlated with the surfactant loading. PRM desorption showed irreversible behavior in raw Mt, which changed to reversible for organo-Mt samples, and was also correlated with the increase of surfactant loading.Two of the organo-Mt with high surfactant loading (twice the CEC) were assayed for the removal of commercial PRM in coagulation/flocculation tests, and their performance was compared to that of the native clay (Mt). The use of the organo-Mt produced flocculation at a very low ratio (0.5 g L^-1), whereas no flocculation was observed with Mt. These results proved the feasibility of the use of organo-Mt for the treatment of wastewater contaminated with PRM using a low organo-Mt/liquid ratio.