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One of the most challenging characteristics not fully understood yet of the cationic surfactant salt dioctadecyldimethylammonium (DODA+) halide is concerned with the effects of the counterion (usually Br− and Cl−) on the surfactant assembly into vesicle structures in aqueous solution. These counterions play a key role in the self‐organization of DODA+ into bilayer structures. Differential scanning calorimetry (DSC) and dynamic light scattering (DLS) techniques were used here to investigate systematically the effects of the single salts NaCl and NaBr, respectively, on the thermal behavior and structural organization of the cationic dioctadecyldimethylammonium bromide and chloride (DODAB and DODAC) in water. The results undoubtedly indicate that the added Br− or Cl−, respectively, into DODAC and DODAB aqueous dispersions, replaces partially the bound counterions (Cl− and Br−) from the vesicles, yielding formation of DODAB/DODAC mixed vesicles. As a conclusion, single salts may be used to tune the thermal and structural characteristics of cationic vesicles.

Triblock copolymers, such as Pluronic F127 (F127), are pharmaceutically important amphiphilic compounds that self-assemble in aqueous solution either as discrete or entangled micelles, depending on their concentration and temperature, which may function as drug delivery vehicle. Herein, we have synthesized the antimicrobial peptide tritrpticin (TRP3), a tryptophan (Trp)-and arginine (Arg)-rich peptide, sequence VRRFPWWWPFLRR, with a broad spectrum of action against bacteria and fungi, to investigate its interaction with F127 in dilute aqueous solution, by using fluorescence and circular dichroism spectroscopies, differential scanning calorimetry, dynamic light scattering, and zeta potential methods. The combined results indicate that at 50 μmol L −1 TRP3 and up to 700 μmol L −1 F127, these compounds interact together to form F127-bound complexes with the peptide at low concentrations, and immobilized TPR3-containing micelle-like structures at higher concentrations. The F127-TRP3 complexes are stable with varying hydrodynamic size depending on the relative amount of F127, which can be tuned smaller by adjusting the copolymer concentration to values suitable for drug delivery applications in biomedicine.

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The article examines the ambivalent dynamics of activism in social media and online platforms. Made up of Brazilian researchers from areas such as Communication, Visual Arts and Design, Anthropology, Computer Science and Engineering, the group analysed 213,083 images shared on Instagram that are part of the hashtag »MariellePresente«, an online political manifestation that arose in response from the assassination of Brazilian concilwoman Marielle Franco in 2018, an unsolved case. After collecting images with a Python programming language script, the group used two Computer Vision/Artificial Intelligence tools to read them (Google Cloud Vision and YOLO Darknet). The results show the capitalistic logics inscribed into these technologies and also shed light on the role played by both online activism and data analysis tools. Thus, the consequences of the shift of political movements online became apparent: by helping activism to find its public, online platforms simultaneously subject its cause to demands of 21st century's digital capitalism (Zuboff 2019; Srnicek 2017; Bruno 2013; Crary 2013; Beiguelman 2020).