Radiometric Analysis of Silver Iodide Sols

With the ultimate goal to investigate (a) the formation of the solid phase by precipitation from electrolytic solutions, and (b) processes characteristic of the interaction between the solid phase and the electrolytic solution, the well-known radiometric methods of analyses have been applied, as well as new radiometric methods for the analysis of colloidal system developed. The methods applied are extremely sensitive, selective, and accurate. The new methods have been checked up by comparison of the obtained results with the standard classical methods, such as X-ray diffraction, turbidimetry, conductometry, differential thermic analysis, and also by published data

Polyphenol-Based Microencapsulated Extracts as Novel Green Insecticides for Sustainable Management of Polyphagous Brown Marmorated Stink Bug (Halyomorpha halys Stål, 1855)

The brown marmorated stink bug (Halyomorpha halys Stål, 1855) is an invasive polyphagous species that threatens fruit growing both in the United States and Europe. Many pesticide active ingredients have been studied in H. halys management, but for sustainable fruit growing, which implies the reduction of chemical harm to the environment, new safe insecticides should be implemented into the practice. For this purpose, novel green insecticide based on natural polyphenols of species Stevia rebaudiana (Bertoni) Bertoni and Aronia melanocarpa (Michx.) Elliott 1821 was developed. Stevia leaves (SLE) and Aronia pomace (APE) aqueous extracts were prepared using the ultrasound-assisted extraction method. Optimal extraction conditions for bioactive compounds (total polyphenols, flavonoids, anthocyanins, and flavan-3-ols, respectively) and antioxidant activity were determined using response surface methodology. Bioactive compounds rich SLE and APE were encapsulated in calcium alginate microparticles by the ionic gelation method. Physicochemical characteristics (morphology, size, encapsulation efficiency, loading capacity, and swelling) of microparticles showed very good properties with especially high encapsulation efficiency. Fitting to simple Korsmeyer–Peppa’s empirical model revealed that the underlying release mechanism of polyphenols is Fickian diffusion. SLE loaded microparticles showed very good pesticidal efficiency against Halyomorpha halys, especially on younger larval stages after both contact and digestive treatment. Microparticles loaded with APE did not achieve satisfactory digestive efficiency, but a certain toxic impact has been observed at contact application on all H. halys growth stages. Microparticles loaded with SLS exhibited prolonged insecticidal action against H. halys and could be a potential candidate as a green insecticide whose application could increase fruit growing safety

Radiometric Analysis of Silver Iodide Sols

With the ultimate goal to investigate (a) the formation of the solid phase by precipitation from electrolytic solutions, and (b) processes characteristic of the interaction between the solid phase and the electrolytic solution, the well-known radiometric methods of analyses have been applied, as well as new radiometric methods for the analysis of colloidal system developed. The methods applied are extremely sensitive, selective, and accurate. The new methods have been checked up by comparison of the obtained results with the standard classical methods, such as X-ray diffraction, turbidimetry, conductometry, differential thermic analysis, and also by published data

Direct Evidence of Multicompartment Aggregates in Polyelectrolyte-Charged Liposome Complexes

By means of the combined use of dynamic light scattering and transmission electron microscopy measurements, we provide a direct evidence for the existence of an equilibrium cluster phase in the polyion-induced liposome aggregation, where the liposomes maintain their integrity, with the ability of preserving the aqueous core content from the external medium. We prepared single liposomes containing, in their interior, different CsCl electrolyte solutions at different concentrations (0.1 and 0.01 M, respectively). During the polyion-induced complexation of a mixture of these two differently loaded liposomes, reversible aggregates form, whose multicompartmental structure reveals the simultaneous presence of nonfused liposomes. Clusters composed by mesoscopic-sized vesicles and realized by charged lipids coupled to oppositely charged polyions are playing an increasingly important role as model systems in a variety of phenomena in soft matter and for their potential use in biomedical applications as drug delivery systems. Aggregates of liposomes such as those described in this article, where the electrostatic interactions are the primary driving forces promoting aggregation, may represent a new and interesting class of colloids which give rise to a rich phenomenology with several unusual colloidal behaviors that deserve to be further investigated