Polyurethane-urea microcapsules with limonene oil as the active agent were produced by interfacial polymerization, and their suitability for textile applications was studied. Experimental conditions for the textile substrates impregnation were based on industrial requirements and set up at laboratory scale using a minifoulard. The success of the polymerization reaction leading to the formation of the polyurethane-urea shell was checked by Fourier transform infrared spectroscopy. Particle size distributions and morphology of the microcapsules were studied using a particle size analyzer (Coulter LS230), optical microscopy, and scanning electron microscopy. The effectiveness of the textiles impregnation and the durability of the impregnation effect were evaluated by scanning electron microscopy and by headspace/GC/FID. Under the present research, a product was developed and its performance, in regard to industrial requirements, was successfully tested.
Despite its inclusion in pneumococcal conjugate vaccine 13 (PCV13), Streptococcus pneumoniae serotype 3 remains a major cause of invasive pneumococcal disease in England and Wales. Previous studies have indicated that there are distinct lineages within serotype 3 clonal complex 180 and the clade distributions have shifted in recent years with the emergence of clade II. We undertook whole genome sequencing and genomic analysis of 616 serotype 3 isolates from England and Wales between 2003 and 2018, including invasive and carriage isolates. Our investigations showed that clade II has expanded since 2014 and now represents 50% of serotype 3 invasive pneumococcal disease (IPD) isolates in England and Wales. Genomic analysis of antibiotic resistance and protein antigen genes showed that distinct profiles are present within the clades which could account for the recent emergence of this clade. This investigation highlights the importance and utility of routine whole genome sequencing and its ability to identify new and emerging variation at the single nucleotide level which informs surveillance and will impact future vaccine development.
Microencapsulation reveals numerous advantages over conventional applications of flavors or fragrances. Thus, the goal of this work was to study the release rate of thyme oil through the polylactide (PLA) microcapsules prepared by coacervation. Microcapsules have spherical shape and a mean particle size of 36 μm. The results show that the release of thymol is faster in the first hour and remains almost constant in the next days. Moreover, it was observed that the release of the polar compounds of thyme oil is faster than the apolar ones. The diffusion coefficient in the first hour of release was 1.39 × 10–15 m2/s for thymol and 5.21 × 10–17 m2/s for p-cymene. For a period of 5 days, diffusion coefficients of 3.81 × 10–17 m2/s for thymol and 1.43 × 10–18 m2/s for cymene were determined. The diffusion of thyme oil from the PLA cross-linked membrane was dependent on the microcapsules morphological characteristics.
The objective of this work is to prepare microcapsules of polylactide-containing thyme oil by coacervation using a variety of nonionic surfactants with different hydrophilic−lipophilic balance (HLB) values and evaluate the encapsulation efficiency of polar and apolar compounds of oil. Thus, Tween 20, Tween 80, Tergitol 15-S-9, and a combination of Tergitol 15-S-9 with Span 85 have been used. The HLB value was comprised between 11 and 16.5. For all the studied cases, microcapsules are spherical in shape and have bimodal particle size distribution with mean size between 30 and 40 μm. The amount of encapsulated thyme oil reaches a maximum of 65% for Tergitol 15-S-9, a polyglycol ether surfactant with a HLB value of 13.3. The results confirm the dependence of the encapsulation efficiency as result of the hydrophobic properties of the surfactants. Moreover, it was confirmed a preferential encapsulation of apolar compounds of thyme oil in detriment of polar ones.
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