Low temperature phase transition in KOH and KOD

Dielectric constant and differential scanning calorimetry measurements have shown a transition to a new phase in both KOH (at 233 K) and KOD (at 257 K); the shape of the dielectric anomaly suggests electrical ordering at low temperature. Structural parameters obtained from high resolution neutron powder diffraction data demonstrate the ordering to be antiferroelectric. A preliminary account is given of the structures at 293 K and 77 K.     

Dielectric properties of CsBr single crystals-effect of d.c. bias

The dielectric properties of CsBr single crystals, both virgin and γ-irrddiated have been measured as a function of frequency (10³–10⁵Hz), temperature (300–575 K) and d.c. bias (0–350 V cm⁻¹). γ-irradiation produces colour centres in these crystals and consequently an increase in space charge density is observed. D.c. bias has brought in considerable changes in dielectric constant (ϵ') and loss (tanδ) of these crystals particularly at low frequencies and high temperatures. An attempt has been made to understand these data qualitatively through barrier layer formation.     

Structural Investigation of the Interaction Mechanism between Chlorogenic Acid and AMPA Receptor via In Silico Approaches

Chlorogenic acid (CGA), an important metabolite in natural plant medicines such as honeysuckle and eucommia, has been shown to have potent antinociceptive effects. Nevertheless, the mechanism by which CGA relieves chronic pain remains unclear. α-amino-3-hydroxy-5-methyl-4-isooxazolpropionic acid receptor (AMPAR) is a major ionotropic glutamate receptor that mediates rapid excitatory synaptic transmission and its glutamate ionotropic receptor AMPA type subunit 1 (GluA1) plays a key role in nociceptive transmission. In this study, we used Western blot, surface plasmon resonance (SPR) assay, and the molecular simulation technologies to investigate the mechanism of interaction between CGA and AMPAR to relieve chronic pain. Our results indicate that the protein expression level of GluA1 showed a dependent decrease as the concentration of CGA increased (0, 50, 100, and 200 μM). The SPR assay demonstrates that CGA can directly bind to GluA1 (K_D = 496 μM). Furthermore, CGA forms a stable binding interaction with GluA1, which is validated by molecular dynamics (MD) simulation. The binding free energy between CGA and GluA1 is −39.803 ± 14.772 kJ/mol, where van der Waals interaction and electrostatic interaction are the major contributors to the GluA1–CGA binding, and the key residues are identified (Val-32, Glu-33, Ala-36, Glu-37, Leu-48), which play a crucial role in the binding interaction. This study first reveals the structural basis of the stable interaction between CGA and GluA1 to form a binding complex for the relief of chronic pain. The research provides the structural basis to understand the treatment of chronic pain and is valuable to the design of novel drug molecules in the future.     

Bis(indenyl)titanacyclopentan und bis(indenyl)(η2-ethylen)titan

Attempts to prepare (di-η⁵-indenyl)(η²-ethylene)methyltitamum (A) from (ind)₂TiCl, MeMgCl and ethylene led to the disproportionation products bis(η⁵-indenyl)titanacyclopentane (5) and bis(η⁵-indenyl)dimethyltitanium (4) instead of to A. 5 dissociates reversibly upon heating from −80 to −20°C giving (di-η⁵-indenyl)(η²-ethylene)titanium (6) and ethylene.     

Synthesis and structural characterisation of the mixed-metal cluster cation [Nb(η5-C5H4R)2{AuP(C6H5)3}2]+ with R = H or Si(CH3)3

Triangular “NbAu₂” cluster compounds have been prepared by the reaction of [Nb(η⁵-C₅H₄R)₂H₃] (R = H, Si(CH₃)₃) with gold(I) salts and the structure of [Nb{η⁵-C₅H₄Si(CH₃)₃}₂{AuP(C₆H₅)₃}₂] PF₆ has been determined by X-ray diffraction.