Higher-Order Semimetals and Chiral Hinge States in Topolectrical Circuit Model

We propose a 3D topolectrical (TE) network that can be tuned to realize various higher-order topological gapless and chiral phases. We first study a higher-order Dirac semimetal phase that exhibits a hinge-like Fermi arc linking the Dirac points. This circuit can be extended to host highly tunable first- and second-order Weyl semimetals phases by introducing a non-reciprocal resistive coupling in the x − y plane that breaks time reversal symmetry. The first- and second-order Weyl points are connected by zero-admittance surface and hinge states, respectively. We also study the emergence of first- and second-order chiral modes induced by resistive couplings between similar nodes in the z-direction. These modes respectively occur in the midgap of the surface and hinge admittance bands in our circuit model without the need for any external magnetic field.

Celkové inhalačné anestetiká – farmakodynamika, farmakokinetika a chirálne vlastnosti

Since the advent of nitric oxide, diethyl ether, chloroform and cyclopropane, the greatest advancement in the area of general inhalational anesthetics has been achieved by the introduction of fluorinated anesthetics and the relevant chiral techniques. This progress led to marked decrease in mortality rates in anesthesia. In the group of chiral fluorinated compounds, halothane (Fluotan®), isoflurane (Foran®), desflurane (Supran®) and enflurane (Ehran®) are deployed as volatile anesthetics. Chiral anesthetics possess a stereogenic center in their molecules and thus exist as two enantiomers (S)-(+) and (R)-(–). Although these chiral anesthetics are used as racemates, it is crucial to study besides the bioactivities of the racemic compounds also the biological activity and other properties of the particular enantiomers. The present survey discusses the drug category known as inhalational anesthetics in regard to their chiral aspects. These compounds exhibit marked differences between the (R) and (S)-enantiomers in their pharmacodynamics, pharmacokinetics and toxicity. The main analytical technique employed in the enantioseparation of these compounds is gas chromatography (GC). This review lists the individual chiral phases (chiral selectors) used in the enantioseparation as well as in pharmacokinetic studies. The possibilities of preparation of these compounds in their enantiomerically pure form by means of stereoselective synthesis are also mentioned.

On the factors influencing the chiroptical response of conjugated polymer thin films

Chiral phases induced in conjugated polymers are a promising approach to producing thin films with strong circular dichroism (CD) and circularly polarised (CP) luminescence. However, a detailed understanding towards the...

Inhomogeneous phases in the quark-meson model with explicit chiral-symmetry breaking

We investigate the existence of inhomogeneous chiral phases in the quark-meson model with explicit chiral-symmetry breaking. We find that the inhomogeneous region shrinks with increasing pion masses but survives for the physical value of mπ. The instability towards inhomogeneous matter occurs in the scalar channel, while pseudoscalar modes are disfavored.