Hydrogen trioxide (HO3) has long been postulated as a key intermediate in important atmospheric processes but has proved difficult to detect. The molecule was unequivocally detected in experiments based on neutralization-reionization and neutralization-reionization/collisionally activated dissociation mass spectrometry, using protonated ozone (HO3+) as the charged precursor. Hydrogen trioxide is a relatively stable species and has a H-O-O-O connectivity and a lifetime exceeding 10(-6) seconds at ambient temperature.

Pseudomonas aeruginosa is a ubiquitous organism and opportunistic pathogen that can cause persistent infections due to its peculiar antibiotic resistance mechanisms and to its ability to adhere and form biofilm. The interest in the development of new approaches for the prevention and treatment of biofilm formation has recently increased. The aim of this study was to seek new non-biocidal agents able to inhibit biofilm formation, in order to counteract virulence rather than bacterial growth and avoid the selection of escape mutants. Herein, different essential oils extracted from Mediterranean plants were analyzed for their activity against P. aeruginosa. Results show that they were able to destabilize biofilm at very low concentration without impairing bacterial viability. Since the action is not related to a bacteriostatic/bactericidal activity on P. aeruginosa, the biofilm change of growth in presence of the essential oils was possibly due to a modulation of the phenotype. To this aim, application of machine learning algorithms led to the development of quantitative activity–composition relationships classification models that allowed to direct point out those essential oil chemical components more involved in the inhibition of biofilm production. The action of selected essential oils on sessile phenotype make them particularly interesting for possible applications such as prevention of bacterial contamination in the community and in healthcare environments in order to prevent human infections. We assayed 89 samples of different essential oils as P. aeruginosa anti-biofilm. Many samples inhibited P. aeruginosa biofilm at concentrations as low as 48.8 µg/mL. Classification of the models was developed through machine learning algorithms.

Steam distillation is known to be the most prevalent method of essential oil extraction. Despite many studies on extraction methods, there is no report about the impact of distillation process duration on the yield and oil quality. A new 24-h steam distillation process for extraction of plant essential oils is presented. For improving the total yield, prolonged and continued isolation was used. A selection of plant species from Lamiaceae and Apiaceae families was subjected to direct steam distillation and essential oils were collected at different times (1, 2, 3, 6, 12 and 24 h). The analysis included either annual or perennial species monitored in terms of different harvesting time. From these studies, it is conclusively that there is no rule about appropriate extraction time, and different plants need different periods for the essential oils to achieve the desired quality or quantity of extract. Thus, extraction duration is directly dependent on what the study is conducted for.

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Modification of hydroxyl-terminated self-assembled monolayer (HO-SAM) surfaces by collision of low-energy (15 eV) hyperthermal Si(CH3)3+ ions is shown to lead to Si-O bond formation and terminal trimethylsilyl ether formation. Modification was verified by in situ mass spectrometry using chemical sputtering with CF3+ ions (70 eV), ex situ secondary ion mass spectrometric analysis (12 kV Ga+ primary ion beam), and through X-ray photoelectron spectroscopy by monitoring Si (2s). The nature of the surface modification was further established by analysis of synthetic SAM surfaces made up of mixtures of the trimethylsilyl-11-mercapto-1-undecane ether and various proportions of the hydroxyl-terminated mercaptan (11-mercapto-1-undecanol). These mixed surfaces, as well as the spectroscopic data, indicate that ca. 30% of the hydroxyl chains are covalently modified at saturation coverage. Analogous surface transformations are achieved using Si(CH3)2F+ and Si(CH3)2C6H5+.