Thermal analysis of the oxide–chloride systems GdCl3–Gd2O3 and GdCl3–KCl–Gd2O3

Journal of Thermal Analysis and Calorimetry - The thermal analysis of the oxide–chloride systems GdCl3–Gd2O3 and GdCl3–KCl–Gd2O3 with the Gd2O3 content up to...     

Catalytic Asymmetric Dearomatization by Visible‐Light‐Activated [2+2] Photocycloaddition

A novel method for the catalytic asymmetric dearomatization by visible‐light‐activated [2+2] photocycloaddition with benzofurans and one example of a benzothiophene is reported, thereby providing chiral tricyclic structures with up to four stereocenters including quaternary stereocenters. The benzofurans and the benzothiophene are functionalized at the 2‐position with a chelating N‐acylpyrazole moiety which permits the coordination of a visible‐light‐activatable chiral‐at‐rhodium Lewis acid catalyst. Computational molecular modeling revealed the origin of the unusual regioselectivity and identified the heteroatom in the heterocycle to be key for the regiocontrol.     

Self-directed chain reaction by small ketones with the dangling bond site on the Si(100)-(2 x 1)-H surface: acetophenone, a unique example

Using scanning tunneling microscope (STM) at 300 K, we studied the growth of one-dimensional molecular assemblies (molecular lines) on the Si(100)-(2 x 1)-H surface through the chain reaction of small ketone (CH 3COCH 3, PhCOPh, and PhCOCH 3) molecules with dangling bond (DB) sites of the substrate. Acetone and benzophenone show the growth of molecular lines exclusively parallel to the dimer row direction. In contrast, acetophenone molecules show some molecular lines perpendicular, in addition to parallel, to the dimer row direction. Most of the molecular lines perpendicular to the dimer row direction were grown by self-turning the propagation direction of a chain reaction from parallel to perpendicular directions relative to the dimer row. A chiral center created upon adsorption of an acetophenone molecule allows the adsorbed molecules to align with identical as well as alternate enantiomeric forms along the dimer row direction, whereas such variations in molecular arrangement are not observed in the case of acetone and benzophenone molecules. The observed molecular lines growth both parallel and perpendicular to dimer row directions appears to be unique to acetophenone among all the molecules studied to date. Hence, the present study opens new possibility for fabricating one-dimensional molecular assemblies of various compositions in both high-symmetry directions on the Si(100)-(2 x 1)-H surface.     

Real-time detection of<Emphasis Type="SmallCaps"> L</Emphasis>-glutamate released from C6 glioma cells using a modified enzyme-luminescence method

There is an increasing interest in new strategies to detect neurotransmitters released from nerve cells in real time for brain science, drug assessment, and so on. Previously we reported real-time monitoring of dopamine release from nerve model cells by enzyme-catalyzed luminescence measurement with tyramine oxidase and peroxidase. In the present study, the system was modified with glutamate oxidase instead of tyramine oxidase to detect L-glutamate sensitively (≈ 10 nM) and rapidly with high temporal resolution (<1 s). We applied this modified method successfully to perform real-time monitoring of L-glutamate release from brain model cell (C6 glioma cell) using a luminescence plate reader upon stimulation with high concentration of KCl (>10 mM) or 5-hydroxytryptamine (>1 μM). The measurement solution was not toxic and therefore the L-glutamate release from the cell was measured by the second stimulation after exchanging the measurement solution. We conclude that the developed monitoring system is suitable for real-time detection of dynamic L-glutamate release from nerve cells in vitro and will be suitable for application in assessment of drugs acting on the nervous system. Figure Enzyme luminescence detection of L-glutamate released from cells