Microgel-like aggregates of isotactic and atactic poly(methacrylic acid) chains in aqueous alkali chloride solutions as evidenced by light scattering

Peer reviewe

The Impact of Environmental Educational Programs in Promoting Insects Conservation Awareness: A Scoping Review

The decline of biodiversity and natural habitats, and the lack of progress in society's behaviour towards conservation, has prompted research into effective educational programs. Studies have shown that positive emotions towards nature, particularly in relation to the innate human predisposition towards the natural environment, can encourage environmentally friendly actions. As people's attitudes towards species are linked to familiarity and experiences, insects, and other invertebrates, despite their vital role in ecosystems, are often underappreciated and face inequalities in research and conservation. Negative attitudes towards insects are shaped by cultural and educational factors. Hence, education, particularly environmental education, can play a significant role in changing preconceptions and attitudes towards insects and fostering positive behaviour towards biodiversity conservation. This study presents a scoping review of environmental education programs focused on enhancing students' awareness of insects and their significance in the ecosystem (from 2000 to 2022). The aim was to analyse the effects of intervention programs and key characteristics that contributed to their efficiency. The review highlights the importance of program duration, outdoor experiences, and the use of inquiry-based and experiential learning methods in promoting positive attitudes and knowledge about insects. The findings have implications for the design and implementation of effective environmental education programs targeting insect awareness

Chain dynamics and intermolecular association in dilute aqueous solutions of isotactic and atactic Poly(Methacrylic acid) : Effect of NaCl concentration

Dynamic and static light scattering measurements were performed on isotactic and atactic forms of poly (methacrylic acid), iPMA and aPMA, respectively, in order to perform a wide survey of their molecular properties and chain dynamics in water as functions of tacticity, degree of neutralization, alpha(N), and salt concentration, c(s). The molecular parameters of PMA chains were analyzed at low alpha(N) and chain dynamics (diffusion coefficients and in this connection the polyelectrolyte slow mode behavior) at higher alpha(N). The data revealed that both PMAs form microgel-like aggregates with a core-shell structure at low alpha(N) ( = 0 and 0.25 for aPMA and iPMA, respectively). The distribution of the hydrophilic and hydrophobic functional groups within the aggregates and their compactness depended considerably on chain tacticity and for aPMA also on c(s). Further, the effect of c(s) on the polyelectrolyte slow diffusion coefficient, D-s, of partly (0.25Peer reviewe

The Role of Specific Interaction in Phase Behavior of Polyelectrolyte-Surfactant-Water Mixtures

Aqueous phase behavior and structures of phases were studied in systems containing sodium poly(styrenesulfonate), NaPSS, and complex salt CTAPSS, formed between cetyltrimethylammonium cations, CTA+, and PSS- anions. It was shown that hydrophobic interaction of the polyion styrene groups with surfactant aggregates, which supports the strong electrostatic attraction between CTA+ and PSS-, has a significant effect on phase behavior and structures. Only the disordered micellar (L1) and the ordered hexagonal (H1) phase were found that are connected over a broad two-phase region of L1-H1 coexistence. At water contents above 60 wt%, CTAPSS is easily dissolved in proportion to the amount of added NaPSS, whereas at lower water contents a large excess of NaPSS is needed to dissolve CTAPSS. Phase separation in the two-phase region is controlled by two tendencies: (i) to maximize the contact between the hydrophobic groups and micelles (assisted by hydrophobic interaction) and (ii) to form as dense phase as possible (assisted by both, electrostatic and hydrophobic interactions). Structural characteristics of soluble non-stoichiometric complexes from the L1 phase show that hydrophobic interaction contributes also to a relatively small size of PSS-induced micelles and leads to a network-like association between PSS chains in which micelles serve as cross-links.status: publishe

Phase Diagram and Structures in Mixtures of Poly(styrenesulfonate anion) and Alkyltrimethylammonium Cations in Water: Significance of Specific Hydrophobic Interaction

Mixtures of polyelectrolytes and oppositely charged surfactants show very rich phase behavior that is influenced by surfactant–ion and polyion properties and by water content. A general feature is associative phase separation as a result of strong electrostatic interactions, whereas the effect of eventual more specific interactions (e.g., hydrophobic) has not been thoroughly investigated. In this paper, we report a detailed study on phase behavior and structures in poly­(styrenesulfonate anion) (PSS^–)–cetyltrimethylammonium cation (CTA⁺)–water mixtures that are characterized by a hydrophobic interaction between the styrene groups of PSS^– and the micelle interior. Structures of various phases were determined by small-angle X-ray scattering, and results indicated the presence of a disordered micellar and an ordered hexagonal phase; no cubic phase was found. The general conclusion is that the highlighted hydrophobic interaction promotes dissolution of CTAPSS when the polyion salt is added and provides further stabilization of the dense phase when the surfactant salt is added

Viscosity of plasma as a key factor in assessment of extracellular vesicles by light scattering

Extracellular vesicles (EVs) isolated from biological samples are a promising material for use in medicine and technology. However, the assessment methods that would yield repeatable concentrations, sizes and compositions of the harvested material are missing. A plausible model for the description of EV isolates has not been developed. Furthermore, the identity and genesis of EVs are still obscure and the relevant parameters have not yet been identified. The purpose of this work is to better understand the mechanisms taking place during harvesting of EVs, in particular the role of viscosity of EV suspension. The EVs were harvested from blood plasma by repeated centrifugation and washing of samples. Their size and shape were assessed by using a combination of static and dynamic light scattering. The average shape parameter of the assessed particles was found to be ρ ~ 1 (0.94–1.1 in exosome standards and 0.7–1.2 in blood plasma and EV isolates), pertaining to spherical shells (spherical vesicles). This study has estimated the value of the viscosity coefficient of the medium in blood plasma to be 1.2 mPa/s. It can be concluded that light scattering could be a plausible method for the assessment of EVs upon considering that EVs are a dynamic material with a transient identity

The neurotropic black yeast Exophiala dermatitidis induces neurocytotoxicity in neuroblastoma cells and progressive cell death

The neurotropic and extremophilic black yeast Exophiala dermatitidis (Herpotrichellaceae) inhabits diverse indoor environments, in particular bathrooms, steam baths, and dishwashers. Here, we show that the selected strain, EXF-10123, is polymorphic, can grow at 37 °C, is able to assimilate aromatic hydrocarbons (toluene, mineral oil, n-hexadecane), and shows abundant growth with selected neurotransmitters (acetylcholine, gamma-aminobutyric acid, glycine, glutamate, and dopamine) as sole carbon sources. We have for the first time demonstrated the effect of E. dermatitidis on neuroblastoma cell model SH-SY5Y. Aqueous and organic extracts of E. dermatitidis biomass reduced SH-SY5Y viability by 51% and 37%, respectively. Melanized extracellular vesicles (EVs) prepared from this strain reduced viability of the SH-SY5Y to 21%, while non-melanized EVs were considerably less neurotoxic (79% viability). We also demonstrated direct interactions of E. dermatitidis with SH-SY5Y by scanning electron and confocal fluorescence microscopy. The observed invasion and penetration of neuroblastoma cells by E. dermatitidis hyphae presumably causes the degradation of most neuroblastoma cells in only three days. This may represent a so far unknown indirect or direct cause for the development of some neurodegenerative diseases such as Alzheimer\u27s