ionic environment
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Ionic liquids (ILs) have attracted increasing attention both in the scientific community and the industry in the past two decades. Their risk of being inevitable released to ecosystem lights up the urgent research on their toxicity to the environment. To reduce the time and capital consumption on testing tremendous ILs ecotoxicity experimentally, it is essential to construct predictive models for estimating their toxicity. The objective of this study is to provide a new approach for evaluating the ecotoxicity of ILs. A comprehensive ecotoxicity dataset for Vibrio fischeri involving 142 ILs, was collected and investigated. The electrostatic potential surface areas (SEP) of separate cations and anions of ILs were firstly applied to develop predictive models for ecotoxicity on Vibrio fischeri. In addition, an intelligent algorithm named extreme learning machine (ELM) was employed to establish the predictive model. The squared correlation coefficients (R2), the average absolute error (AAE%) and the root-mean-square error (RMSE) of the developed model are 0.9272, 0.2101 and 0.3262 for the entire set, respectively. The proposed approach based on the high R2 and low deviation has remarkable potential for predicting ILs ecotoxicity on Vibrio fischeri.
The availability of ionic liquids (ILs) in wide areas of application often results in the requirement on their determination. The attention is also often focused on the knowledge of hydrophobicity as it plays a key role in the biological effects, in the assessment of environmental risk and in the prediction of the fate of chemicals in the environment and of its influence on retention in RP HPLC. One can get information regarding hydrophobicity and retention mechanism if quantitative structure-retention relationships (QSRRs) are identified. The QSRRs were derived for logarithms of retention factors extrapolated to a pure water (or aqueous buffer) eluent, log k(w), determined for the pyridinium and imidazolium ionic liquid (IL) cations on two C8 (Supelcosil LC-8-DB, Symmetry C8) and two C18 (ACE 5 C18, Symmetry C18) stationary phases with isocratic elution by a mobile phase consisting of acetonitrile/40 mM phosphate buffer. The analyses of ILs were performed at a flow rate of 1 mL min(-1) with UV detection at 218 nm. The QSRRs were derived based on the retention parameters determined experimentally and the structural descriptors of test analytes from molecular modeling. Separations of ILs were obtained with aqueous acetonitrile buffered at pH 3.55 mobile phases. The statistically most significant two-parameter QSRR regression equations related log k(w) to the solvent accessible surface (SAS) of the analytes and the differences in the energies of the highest occupied and the lowest unoccupied molecular orbitals (diffHL). These equations were especially good in case of columns with the highest carbon loads and larger specific surface areas, i.e. Symmetry C18 and Symmetry C8. On the other hand, the column ACE 5 C18 appeared to produce the best quality separations of the ILs studied. The QSRRs derived in the research shed light on the molecular mechanism of HPLC separation of ILs and helped to predict their relative separations.
- MeSH
- chemické modely MeSH
- chromatografie s reverzní fází metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- iontové kapaliny chemie MeSH
- kationty chemie MeSH
- molekulární struktura MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ionic liquids are increasingly used for their superior properties. Four water-immiscible ionic liquids (butyltriethylammonium bis(trifluoromethylsulfonyl)imide, octyltriethylammonium bis(trifluoromethylsulfonyl)imide, dodecyltriethylammonium bis(trifluoromethylsulfonyl)imide, butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and their water miscible precursors (bromides) were synthesized in a microwave reactor and by conventional heating. The best conditions for microwave-assisted synthesis concerning the yield and the purity of the product are proposed. The heating in the microwave reactor significantly shortened the reaction time. Biocide and ecotoxic effects of synthesized ionic liquids and their precursors were investigated. All tested compounds had at least a little effect on the growth or living of microorganisms (bacteria or mold). The precursor dodecyltriethylammonium bromide was found to be the strongest biocide, but posed a risk to the aquatic environment due to its relatively high EC50 value in the test with Vibrio fischeri. We assumed that apart from the alkyl chain length, the solubility in water, duration of action, or type of anion can influence the final biocide and ecotoxic effect.
- MeSH
- Aliivibrio fischeri účinky léků MeSH
- amoniové sloučeniny chemie MeSH
- antibakteriální látky chemická syntéza farmakologie MeSH
- antifungální látky chemická syntéza chemie farmakologie MeSH
- ekotoxikologie metody MeSH
- imidazoly chemie MeSH
- iontové kapaliny chemická syntéza farmakologie MeSH
- kvartérní amoniové sloučeniny chemická syntéza farmakologie MeSH
- mikrovlny MeSH
- preklinické hodnocení léčiv metody MeSH
- Publikační typ
- časopisecké články MeSH
Progressive cerebral deposition of amyloid beta occurs in Alzheimers disease and during the aging of certain mammals (human, monkey, dog, bear, cow, cat) but not others (rat, mouse). It is possibly due to different amino acid sequences at positions 5, 10 and 13. To address this issue, we performed series of 100 ns long trajectories (each trajectory was run twice with different initial velocity distribution) on amyloid beta (1-42) with the human and rat amino acid sequence in three different environments: water with only counter ions, water with NaCl at a concentration of 0.15 M as a model of intracellular Na(+) concentration at steady state, and water with NaCl at a concentration of 0.30 M as a model of intracellular Na(+) concentration under stimulated conditions. We analyzed secondary structure stability, internal hydrogen bonds, and residual fluctuation. It was observed that the change in ionic strength affects the stability of internal hydrogen bonds. Increasing the ionic strength increases atomic fluctuation in the hydrophobic core of the human amyloid, and decreases the atomic fluctuation in the case of rat amyloid. The secondary structure analyses show a stable α-helix part between residues 10 and 20. However, C-terminus of investigated amyloids is much more flexible showing no stable secondary structure elements. Increasing ionic strength of the solvent leads to decreasing stability of the secondary structural elements. The difference in conformational behavior of the three amino acids at position 5, 10 and 13 for human and rat amyloids significantly changes the conformational behavior of the whole peptide.
- MeSH
- amyloidní beta-protein chemie MeSH
- chlorid sodný chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- osmolární koncentrace MeSH
- peptidové fragmenty chemie MeSH
- povrchové vlastnosti MeSH
- sekundární struktura proteinů MeSH
- sekvence aminokyselin MeSH
- simulace molekulární dynamiky * MeSH
- stabilita proteinů MeSH
- terciární struktura proteinů MeSH
- voda chemie MeSH
- vodíková vazba MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Risk Assessment: The qualified expert assessment of potential ecological/environmental and health risks rising from the planned industrial, transport and waste treatment facilities and other construction activities becomes indispensable. Whereas the initial phase of risk assessment, its identification or potential human exposure are of pure scientific character, the actual risk assessment increasingly assumes the arbitrary aspects (e.g. safety coefficients), risk communication, its control and management by way of psychological aspects; collective decision making then becomes a hotly debated political issue. Risk Perception: When evaluating perception of environmental risks, psychosocial and psychosomatic factors may be of fundamental importance. This is the case in particular where our knowledge of the true health consequences of exposure to given factor is incomplete or its action is within the range of values where we do not anticipate the measurable biological effect. This applies not only in the case of the indoor environment related complains but also e.g. to that of non-ionizing electromagnetic radiation and electro-ionic microclimate. A serious consequence found in the syndrome of mass hysteria is the fact that due to differently motivated disinformation, part of the population can suffer from some psychosomatic symptoms. Those imply objective suffering and deterioration quality of life for those affected. Challenges for Prevention: The prevention of such conditions can either be systematic: early educational or popularisation campaigns, specific health education orientated to the development of industrial, transportation, or other types of constructions, and integration of the local civic activities in the program. The purpose of this should not be a cheap belittling of the risk but reasonable explaining of its acceptable rate, and also the likely advantage to benefit from the realization of the structures. Any later efforts to inform the public about the true state of affairs is usually accepted with distrust and disbelief, in belief this information had been well-paid by the government, industry and market forces, the military or some other institution trying to camouflage the actual condition.
- MeSH
- ekologie * metody MeSH
- hodnocení rizik MeSH
- lidé MeSH
- primární prevence * metody MeSH
- psychosomatické poruchy * etiologie MeSH
- vystavení vlivu životního prostředí prevence a kontrola škodlivé účinky MeSH
- zdraví - znalosti, postoje, praxe * MeSH
- zohlednění rizika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
