12 research outputs found
Quaternary Ammonium Compounds (QACs) and Ionic Liquids (ILs) as Biocides: From Simple Antiseptics to Tunable Antimicrobials
Quaternary ammonium compounds (QACs) belong to a well-known class of cationic biocides with a broad spectrum of antimicrobial activity. They are used as essential components in surfactants, personal hygiene products, cosmetics, softeners, dyes, biological dyes, antiseptics, and disinfectants. Simple but varied in their structure, QACs are divided into several subclasses: Mono-, bis-, multi-, and poly-derivatives. Since the beginning of the 20th century, a significant amount of work has been dedicated to the advancement of this class of biocides. Thus, more than 700 articles on QACs were published only in 2020, according to the modern literature. The structural variability and diverse biological activity of ionic liquids (ILs) make them highly prospective for developing new types of biocides. QACs and ILs bear a common key element in the molecular structureâquaternary positively charged nitrogen atoms within a cyclic or acyclic structural framework. The state-of-the-art research level and paramount demand in modern society recall the rapid development of a new generation of tunable antimicrobials. This review focuses on the main QACs exhibiting antimicrobial and antifungal properties, commercial products based on QACs, and the latest discoveries in QACs and ILs connected with biocide development
Postglacial Paleoceanographic Environments in the Barents and Baltic Seas
This paper presents reconstructions of ice sheet boundaries, lacustrine and marine paleobasins, as well as the connections of the Barents and Baltic seas with the North Atlantic from the Last Glacial Maximum to the Holocene. The reconstructions are based on original and published data obtained from the northern and western parts of the Barents Sea and Baltic depressions with account for the available regional schematic maps of deglaciation. The early deglaciation of the ScandinavianâBarents ice sheet culminated with the BĂžlling-AllerĂžd interstadial (14.5â12.9 cal ka BP), which was characterized by a more vigorous Atlantic meridional overturning circulation (AMOC) and a corresponding increase in surface Atlantic water inflow into the Barents Sea through deep troughs. The Baltic Ice Lake (BIL) remained a dammed-up isolated basin during deglaciation from 16.0 to 11.7 cal ka BP. In the Younger Dryas (YD), the lake drained into the North Sea and was replaced by a brackish Yoldia Sea (YS) at the beginning of the Holocene (Preboreal, 11.7â10.7 cal ka BP), due to a limited connection between two basins through the NĂ€rke Strait. In the Barents Sea, the next increase in the Atlantic water influx into the deep basins corresponded to terminal YD and Preboreal events with a culmination in the Early Holocene. The Yoldia Sea became a lake again during the next stage, the Ancylus (~10.7â8.8 cal ka BP). Atlantic water inflow both into the Barents and Baltic seas varied during the Holocene, with a maximum contribution in the Early Holocene, when the Littorina Sea (LS, 8â4 cal ka BP) connection with the North Sea via the Danish Straits was formed to replace the Ancylus Lake. The recent, post-Littorina stage (PS, the last 4 cal ka) of the Baltic Sea evolution began in the Late Holocene
Ionic Liquids As Tunable Toxicity Storage Media for Sustainable Chemical Waste Management
Storage and handling
of toxic wastes is a top-priority challenge
for sustainable development and public health. In recent years, the
risk of irreversible environmental pollution has been increasing gradually,
necessitating the development of new concepts in this highly demanding
area. Here, we report a flexible approach to address the problem using
tunable ionic liquids as a carrier and storage medium for chemicals.
Encapsulation in microscale tunable media surrounded by an inert ionic
liquid facilitates the efficient capture of chemicals. The adaptive
character of the designed microscale compartments opens new possibilities
for the waste management of chemicals of a diverse nature. Real-time
field-emission scanning electron microscopy was used to visualize
the formation of microscale compartments upon the sequestration of
chemicals in ionic liquids. Ionic liquids captured the chemicals better
than traditional organic solvents or water; moreover, the chemicals
subsequently could be effectively extracted for destruction or utilization.
Our work presents a new model for the sustainable management of chemical
wastes; the concept was evaluated for a number of multiton chemicals
currently affecting our environment
Cytotoxic Activity of Salicylic Acid-Containing Drug Models with Ionic and Covalent Binding
Three
different types of drug delivery platforms based on imidazolium ionic
liquids (ILs) were synthesized in high preparative yields, namely,
the models involving (i) ionic binding of drug and IL; (ii) covalent
binding of drug and IL; and (iii) dual binding using both ionic and
covalent approaches. Seven ionic liquids containing salicylic acid
(SA-ILs) in the cation or/and in the anion were prepared, and their
cytotoxicity toward the human cell lines CaCo-2 (colorectal adenocarcinoma)
and 3215 LS (normal fibroblasts) was evaluated. Cytotoxicity of SA-ILs
was significantly higher than that of conventional imidazolium-based
ILs and was comparable to the pure salicylic acid. It is important
to note that the obtained SA-ILs dissolved in water more readily than
salicylic acid, suggesting benefits of possible usage of traditional
nonsoluble active pharmaceutical ingredients in an ionic liquid form