ABSTRACT
Pyrolysis of medical waste components combined via a novel systematic combination approach (sequentially binary, ternary, and quaternary copyrolysis) was conducted at 400°C to investigate the synergy between medical waste components in improving chemical characteristics and yields of pyrolytic oil. Pyrolysis of hydrocarbon-polymer-containing materials such as medical gloves and rubber bands produced more than 30% of liquid products with substantial compositions of saturated aliphatic hydrocarbon polymers. On the other hand, moisture- and carbonyl-rich pyrolytic liquid products with low selectivity were obtained from pyrolysis of lignocellulosic biomass waste such as HVS paper (houtvrij schrijfpapier, meaning "writing paper made from wood pulp”) and garden waste. Binary copyrolysis of lignocellulosic biomass and medical gloves exhibited improvement on pyrolytic liquid yield and selectivity toward saturated aliphatic hydrocarbon polymers due to hydrogen donor as the medical glove fraction became dominant. The addition of rubber band to the mixture of HVS paper and medical face masks enhanced the pyrolytic liquid yield. The pyrolysis of the mixture of HVS paper, medical face masks, medical gloves, and either rubber bands or cotton fabrics with mixture ratio of 60:20:10:10 yielded the most optimum pyrolytic liquid yield with significant distribution of alkanes in the pyrolytic liquid products. © 2023 Taylor & Francis Group, LLC.
ABSTRACT
Cationic surfactants have gained significant interest since their introduction. Their properties and adsorption behavior onto different surfaces have driven the development of a plethora of surfactants with distinctive functionalities. This paper reviews self-assembly, intermolecular interactions, and the properties of cationic surfactants also when interacting with co-solutes, which may be small molecules or macromolecules, and surfaces. The versatile properties of single- and double-chain cationic surfactants and other special cationics such as gemini, catanionic, bolaform, amino acid- and sugar-based surfactants, are presented and discussed together with skin toxicity and environmental considerations. The effects of cationic surfactant mixing with other surfactants, polymers, proteins, and DNA are also shown and examined. We also outline established applications of cationic surfactants as disinfectants, in fabric softening, hard surface cleaning, personal care applications, road surfacing, and oil field applications, as well as emerging applications such as soft antimicrobial agents and nucleic acid delivery, which has contributed, for instance, to the enormously successful surfactant-based mRNA COVID-19 vaccines. © 2023 Elsevier B.V.
ABSTRACT
Quantum dots were encapsulated in polymeric phospholipid micelles conjugated to multiple ligands of SARS-CoV-2 spike protein to form fluorescent biomimetic nanoparticles for SARS-CoV-2 (COVID-QDs). Phosphatidylethanolaminepolyethylene glycol (PE:PEG) was appended with bis(4-methylphenyl)sulfone to form PE:PEG:bis-sulfone and self-assembled into micelles around CdSe/CdS core/shell quantum dots via thin-film rehydration. The introduction of the bis-sulfone group the surface of the micelle-encapsulated quantum dots provides multiple sites for conjugation to his-tagged SARS-CoV-2 spike protein via a bisalkylation mechanism. Based on the eluted unconjugated fraction, we estimate that an average of seven spike proteins are conjugated per COVID-QD. We treated an in-vitro model system for the neurovascular unit (NVU) with these COVID-QD constructs to investigate the COVID-QDs, and by proxy SARS-CoV-2, may modulate the NVU leading to the COVID-19 associated neuropathophysiology. © 2022 SPIE