Natural isopropyl cresols have been reported to have antifungal activity. This work is an attempt to examine thymol and carvacrol against 111 fluconazole-sensitive and -resistant Candida isolates. Insight into the mechanism of action was elucidated by flow cytometric analysis, confocal imaging and ergosterol biosynthesis studies. The susceptibility tests for the test compounds were carried out in terms of minimum inhibitory concentrations (MICs), disc diffusion assays and time-kill curves against all Candida isolates by employing standard protocols. Propidium iodide (PI) cell sorting has been investigated by flow cytometric analysis and confocal imaging. Haemolytic activity on human erythrocytes was studied to exclude the possibility of further associated cytotoxicity. Both compounds were found to be effective to varying extents against all isolates, including the resistant strains. In contrast to the fungistatic nature of fluconazole, our compounds were found to exhibit fungicidal nature. Significant impairment of ergosterol biosynthesis was pronouncedly induced by the test entities. Negligible cytoxicity was observed for the same compounds. Furthermore, it was observed that the positional difference of the hydroxyl group in carvacrol slightly changes its antifungal activity. Carvacrol and thymol show strong fungicidal effect against all of the Candida isolates. The mechanisms of action of these natural isopropyl cresols appear to originate from the inhibition of ergosterol biosynthesis and the disruption of membrane integrity.

No abstract

No abstract

Summary Summary To avoid the leakage of phase change materials (PCM) to its surrounding, microencapsulation of PCM in a polymeric shell is highly desirable. These microcapsules ideally should provide a platform to store and release latent heat of the PCM without undergoing any physicochemical transformation of core (PCM) as well as shell (polymer) materials. Several characteristics such as heat transfer efficiency, thermal conductivity, water dispersibility, and durability of the PCM capsules are dependent on the nature of shell materials. In the present study, a random copolymer of poly (methyl methcrylate‐co‐2‐hydroxyethyl methacrylate) poly (MMA‐co‐HEMA) with an optimum ratio of 75/25 (methyl methacrylate (MMA)/2‐hydroxyethyl methacrylate (HEMA)) was used as shell material to encapsulate paraffin wax (PCM), using emulsion solvent evaporation method. The microcapsules of ~5‐μm size with a shell thickness of ~0.8 μm with high encapsulation efficiency (~92.34%) and thermal storage capability (99.85%) were fabricated. In addition to ease of water dispersibility, PHEMA (poly(2‐hydroxyethyl methacrylate)) containing water absorbable shells also exhibit enhanced thermal conductivity from 0.1 to 0.49 W/(m·K) at 25°C in wet state compared with the dry capsule. The capsules show good durability by displaying no significant change in thermal properties and water dispersibility after running through 500 heating/cooling cycles. To test the feasibility of this novel water dispersible microencapsulated PCM, these were mixed with natural rubber latex at various blend ratios, and their thermal behaviour was evaluated. The obtained rubber composite showed good thermoregulation property with enhanced mechanical strength.

Aminolytic chemical recycling is performed for obtaining NN′ diethyl 1,4 benzene dicarboxamide, NN′ dibutyl 1,4 benzene dicarboxamide, and NN′ dihexyl 1,4 benzene dicarboxamide from Polyethylene terephthalate bottle waste. The compounds were characterized through Fourier transform Infrared spectroscopy, Raman spectroscopy, UV–Visible spectroscopy, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis. Thermal properties were also analyzed with the help of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Density Functional Theory (DFT) study has been performed at GGA‐BLYP (Becke's and Lee–Yang–Parr) functional using SZ basis set to investigate the vibrational frequencies and physical parameters. Experimental vibrational frequencies were found in good accord with the experimental values. Calorific values of the products have been determined using bomb calorimeter as per standard ASTM D240. The values have been correlated with increment of methylene units from NN′ diethyl BdCA to NN′ dihexyl BdCA using standard molar enthalpies of carbon and hydrogen. SEM and EDX analysis of the char residues after combustion has also been carried out to insight the effect of N‐alkyl chain length on calorific values. The calorific values of the recovered compounds are comparable to commercial solid fuels and the compounds may find potential applications in aerospace industry.