Basic characteristics of the liquid-glass transition are reviewed, emphasizing its universality and briefly summarizing the most popular phenomenological models. Discussion is focused on a number of alternative models which one way or the other connect the fast and slow degrees of freedom of viscous liquids. It is shown that all these ``elastic'' models are equivalent in the simplest approximation.

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Colloquium : The glass transition and elastic models of glass-forming liquids

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in ...

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine.

Bull. Chem. Soc. Jpn. への投稿のすすめ

Dynamic properties, derived from dielectric relaxation spectra of glass-formers at variable temperature and pressure, are used to characterize and classify any resolved or unresolved secondary relaxation based on their different behaviors. The dynamic properties of the secondary relaxation used include: (1) the pressure and temperature dependences; (2) the separation between its relaxation time τβ and the primary relaxation time τα at any chosen τα; (3) whether τβ is approximately equal to the independent (primitive) relaxation time τ0 of the coupling model; (4) whether both τβ and τ0 have the same pressure and temperature dependences; (5) whether it is responsible for the “excess wing” of the primary relaxation observed in some glass-formers; (6) how the excess wing changes on aging, blending with another miscible glass-former, or increasing the molecular weight of the glass-former; (7) the change of temperature dependence of its dielectric strength Δeβ and τβ across the glass transition temperature Tg; ...

Classification of secondary relaxation in glass-formers based on dynamic properties.

The thermal and physicochemical properties of protic ionic liquids (PILs) are reported. It is highly evident that there has been an extensive range of alkylammonium, imidazolium, and heterocyclic cations paired with many organic and inorganic anions that have been employed to prepare PILs. There has been strong interest in modifying the properties of PILs through the addition of water or other molecular solvents. For many applications, the presence of some water in the PILs is not detrimental, and instead leads to enhanced solvent properties such as lower viscosity, higher conductivities, and lower melting points. It remains an issue of definition though of how to refer to these resulting protic solutions. There is also an ongoing difficulty surrounding how to describe the proton activity in the PILs, analogous to pH in aqueous systems. For a broad range of applications, it has been reported that the acidity/basicity of the PIL or PIL-solvent system is crucial for their beneficial properties. It is expected that the fundamental properties of PILs will continue to be explored, along with continued interest in many existing and new applications, such as in electrochemistry, organic and inorganic synthesis, and biological applications. In particular, there has been a significant interest in a broad- range of PILs for use as electrolytes and incorporation in polymer electrolytes for fuel cells, and other energy storage devices.

Protic Ionic Liquids: Evolving Structure–Property Relationships and Expanding Applications

An intriguing problem in condensed matter physics is understanding the glass transition, in particular the dynamics in the equilibrium liquid close to vitrification Recent advances have been made by using hydrostatic pressure as an experimental variable These results are reviewed, with an emphasis in the insight provided into the mechanisms underlying the relaxation properties of glass-forming liquids and polymers

https://iopscience.iop.org/article/10.1088/0034-4885/68/6/R03/pdf

Supercooled dynamics of glass-forming liquids and polymers under hydrostatic pressure

Although the assortment of antifungal drugs is broad, the most commonly used agents have major drawbacks. Toxicity, serious side effects or the emergence of drug resistance are amongst them. New drugs and drug candidates under clinical trials do not guarantee better pharmacological parameters. These new medicines may appear effective; however; they may cause serious side effects. This current review is focused on the recent findings in the design of quinoline based antifungal agents. This field seems to be especially interesting as 8-hydroxyquinoline and its metal complexes have been well known as antifungals for years. Structural similarities between quinoline based antifungals and allylamines or homoallylamines, e.g. terbinafine is another interesting fact. Quinoline can be identified in a number of synthetic and natural antifungals, which indicates nature's preference for this fragment and identifying it as one of the so-called privileged structures. We have discussed new trends in the design of quinolines with antifungal properties, their possible targets and the structure activity relationships within the antifungal series developed.

Quinoline-based antifungals.

The effect of pressure on the dielectric relaxation of two polyhydroxy alcohols is examined by analysis of existing data on glycerol, together with new measurements on xylitol The fragility, or Tg-normalized temperature dependence, changes with pressure for low pressures, but becomes invariant above 1 GPa When compared at temperatures for which the α-relaxation times are equal, there is no effect of pressure (<1 GPa) on the shape of the α dispersion at higher temperatures However, nearer Tg, pressure broadens the α peak, consistent with the expected correlation of fragility with the breadth of the relaxation function We also observe that the α-relaxation peaks for both glycerol and xylitol show an excess intensity at higher frequencies For xylitol, unlike for glycerol, at lower temperatures this wing disjoins to form a separate peak For both glass formers, elevated pressure causes the excess wing to become more separated from the peak maximum; that is, the properties of the primary and excess intensities are not correlated This implies that the excess wing in glycerol is also a distinct secondary process, although it cannot be resolved from the primary peak

Effect of pressure on the α relaxation in glycerol and xylitol

The relaxation dynamics of a low molecular supercooled liquid, cresolphthalein-dimethylether (KDE), has been investigated in the vicinity of glass transition temperature by dielectric relaxation measurements. Glass transition is approached and studied by the use of isothermal and isobaric paths. Under isobaric condition, the departure of the correlation function of the α-relaxation from exponential decay with time (nonexponentiality) is even less than the intermediate liquids such as glycerol. However, the Tg-scaled temperature dependence of the α-relaxation time, τ, resembles “fragile” glass-formers like orthoterphenyl (OTP). Thus KDE, like propylene carbonate (PC) that has in common a basic chemical structural unit, is an exception to the correlation between “fragility” and nonexponentiality found to hold for most glass formers. The dielectric relaxation measurements with the application of pressure show that KDE has large pressure coefficient of the glass transition temperature, (dTg/dP)P→0, or large a...

Pressure and temperature dependences of the relaxation dynamics of cresolphthalein-dimethylether: Evidence of contributions from thermodynamics and molecular interactions

Dielectric relaxation measurements were carried out on sorbitol as a function of pressure at various temperatures. The almost linear dependence of the structural relaxation times on pressure yields values for the activation volume. In light of results for xylitol and glycerol, the activation volume is found to be an increasing function of molecular size. Because the pressure coefficients of the glass temperature for these polyalcohols are all equal, their fragilities should parallel their respective activation volumes. This expectation is borne out by experimental measurements at ambient pressure. Analysis of the volume dependence of the relaxation times reveals that temperature, rather than density, dominates the structural relaxation of sorbitol. At frequencies higher than the structural relaxation, a secondary process is observed. The weaker pressure sensitivity of the latter effects better resolution of the two peaks at high pressures. The relaxation time for the secondary process is consistent with a calculation from the coupling model based on identification of the secondary process as the precursor to the highly cooperative structural relaxation.

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S. Hensel-Bielowka

Papers

Supercooled dynamics of glass-forming liquids and polymers under hydrostatic pressure

Quinoline-based antifungals.

Effect of pressure on the α relaxation in glycerol and xylitol

Pressure and temperature dependences of the relaxation dynamics of cresolphthalein-dimethylether: Evidence of contributions from thermodynamics and molecular interactions

Dynamics of Sorbitol at Elevated Pressure