The syntheses, biological evaluations, and structure–activity relationships for a series of novel
Z-5-styryl,
E-5-styryl and 5-phenethyl analogs of 2,3,4,5-tetrahydro-1
H-γ-carbolines as potent ...blockers of serotonin, histamine, and adrenergic receptors are disclosed.
Syntheses, biological evaluation, and structure–activity relationships for a series of novel 5-styryl and 5-phenethyl analogs of dimebolin are disclosed. The novel derivatives and dimebolin share a broad spectrum of activities against therapeutically relevant targets. Among all synthesized derivatives, 2,8-dimethyl-5-(
Z)-2-phenylvinyl-2,3,4,5-tetrahydro-1
H-pyrido4,3-
bindole and its 5-phenethyl analog are the most potent blockers of 5-HT
7, 5-HT
6, 5-HT
2C, Adrenergic α
2 and H
1 receptors. The general affinity rank order towards the studied receptors was
Z-
3(2)
>
4(2)
⩾
4(3)
≫
dimebolin, all of them having highest affinities to 5-HT
7 receptors.
Synthesis, biological evaluation and structure-activity relationships for a series of novel gamma- carboline analogues of DimebonsuperTM are described. Among the studied compounds, gamma-carbolines ...3{8} and 3{14} have been identified as potent small molecule antagonists of histamine Hsub1 (ICsub50 = 0.1 microM) and serotonin 5-HTsub6 (ICsub50 = 0.37 microM) receptors, respectively.
Synthesis, biological evaluation and structure–activity relationships for a series of novel γ-carboline analogues of Dimebon
™.
Synthesis, biological evaluation and structure–activity relationships ...for a series of novel γ-carboline analogues of Dimebon
™ are described. Among the studied compounds, γ-carbolines
3
{8} and
3{
14} have been identified as potent small molecule antagonists of histamine H
1 (IC
50
=
0.1
μM) and serotonin 5-HT
6 (IC
50
=
0.37
μM) receptors, respectively.
For quantum electronics, the possibility to finely tune the properties of
magnetic topological insulators (TIs) is a key issue. We studied solid
solutions between two isostructural Z$_2$ TIs, ...magnetic MnBi$_2$Te$_4$ and
nonmagnetic GeBi$_2$Te$_4$, with Z$_2$ invariants of 1;000 and 1;001,
respectively. For high-quality, large mixed crystals of
Ge$_x$Mn$_{1-x}$Bi$_2$Te$_4$, we observed linear x-dependent magnetic
properties, composition-independent pairwise exchange interactions along with
an easy magnetization axis. The bulk band gap gradually decreases to zero for
$x$ from 0 to 0.4, before reopening for $x>0.6$, evidencing topological phase
transitions (TPTs) between topologically nontrivial phases and the semimetal
state. The TPTs are driven purely by the variation of orbital contributions. By
tracing the x-dependent $6p$ contribution to the states near the fundamental
gap, the effective spin-orbit coupling variation is extracted. As $x$ varies,
the maximum of this contribution switches from the valence to the conduction
band, thereby driving two TPTs. The gapless state observed at $x=0.42$ closely
resembles a Dirac semimetal above the Neel temperature and shows a magnetic gap
below, which is clearly visible in raw photoemission data. The observed
behavior of the Ge$_x$Mn$_{1-x}$Bi$_2$Te$_4$ system thereby demonstrates an
ability to precisely control topological and magnetic properties of TIs.
For quantum electronics, the possibility to finely tune the properties of magnetic topological insulators (TIs) is a key issue. We studied solid solutions between two isostructural Z\(_2\) TIs, ...magnetic MnBi\(_2\)Te\(_4\) and nonmagnetic GeBi\(_2\)Te\(_4\), with Z\(_2\) invariants of 1;000 and 1;001, respectively. For high-quality, large mixed crystals of Ge\(_x\)Mn\(_{1-x}\)Bi\(_2\)Te\(_4\), we observed linear x-dependent magnetic properties, composition-independent pairwise exchange interactions along with an easy magnetization axis. The bulk band gap gradually decreases to zero for \(x\) from 0 to 0.4, before reopening for \(x>0.6\), evidencing topological phase transitions (TPTs) between topologically nontrivial phases and the semimetal state. The TPTs are driven purely by the variation of orbital contributions. By tracing the x-dependent \(6p\) contribution to the states near the fundamental gap, the effective spin-orbit coupling variation is extracted. As \(x\) varies, the maximum of this contribution switches from the valence to the conduction band, thereby driving two TPTs. The gapless state observed at \(x=0.42\) closely resembles a Dirac semimetal above the Neel temperature and shows a magnetic gap below, which is clearly visible in raw photoemission data. The observed behavior of the Ge\(_x\)Mn\(_{1-x}\)Bi\(_2\)Te\(_4\) system thereby demonstrates an ability to precisely control topological and magnetic properties of TIs.
Static spherically symmetric black holes are discussed in the framework of higher dimensional gravity with quadratic in curvature terms. Such terms naturally arise as a result of quantum corrections ...induced by quantum fields propagating in the gravitational background. We focus our attention on the correction of the form \({\cal C}^2=C_{\alpha\beta\gamma\delta} C^{\alpha\beta\gamma\delta}\). The Gauss-Bonnet equation in four-dimensional (4D) spacetime enables one to reduce this term in the action to the terms quadratic in the Ricci tensor and scalar curvature. As a result the Schwarzschild solution which is Ricci flat will be also a solution of the theory with the Weyl scalar \({\cal C}^2\) correction. An important new feature of the spaces with dimension \(D > 4\) is that in the presence of the Weyl curvature-squared term a solution necessary differs from the corresponding `classical' vacuum Tangherlini metric. This difference is related to the presence of {\em secondary} or {\em induced} hair. We explore how the Tangherlini solution is modified by `quantum corrections', assuming that the gravitational radius \(r_0\) is much larger than the scale of the quantum corrections. We also demonstrated that finding a general solution beyond the perturbation method can be reduced to solving a single third order ODE (master equation).
