Induction of inverted morphology in brain organoids by vertical-mixing bioreactors

Organoid technology provides an opportunity to generate brain-like structures by recapitulating developmental steps in the manner of self-organization. Here we examined the vertical-mixing effect on brain organoid structures using bioreactors and established inverted brain organoids. The organoids generated by vertical mixing showed neurons that migrated from the outer periphery to the inner core of organoids, in contrast to orbital mixing. Computational analysis of flow dynamics clarified that, by comparison with orbital mixing, vertical mixing maintained the high turbulent energy around organoids, and continuously kept inter-organoid distances by dispersing and adding uniform rheological force on organoids. To uncover the mechanisms of the inverted structure, we investigated the direction of primary cilia, a cellular mechanosensor. Primary cilia of neural progenitors by vertical mixing were aligned in a multidirectional manner, and those by orbital mixing in a bidirectional manner. Single-cell RNA sequencing revealed that neurons of inverted brain organoids presented a GABAergic character of the ventral forebrain. These results suggest that controlling fluid dynamics by biomechanical engineering can direct stem cell differentiation of brain organoids, and that inverted brain organoids will be applicable for studying human brain development and disorders in the future.

Controlling ultralong room temperature phosphorescence in organic compounds with sulfur oxidation state

Sulfur lone pairs in bridged dimers enhance intersystem crossing and phosphorescence through orbital mixing and electrostatic screening.

High-pressure Raman study of the alkaline-earth metal fulleride, Ca2.75C60

The structural stability and electronic properties of [Formula: see text] are probed by means of high-pressure Raman spectroscopy using two different pressure transmitting media that lead to practically identical results. Although [Formula: see text] is isostructural with the rare-earth metal fulleride, [Formula: see text] of the same stoichiometry, the pressure coefficients of characteristic intramolecular [Formula: see text] modes are larger than those in the [Formula: see text] counterpart but similar to those in the pristine [Formula: see text] solid. Since the reduced pressure coefficients in the Sm fulleride have been attributed to strong [Formula: see text] coupling, our findings for the isostructural Ca fulleride are compatible with a reduced orbital mixing and [Formula: see text] coupling.

The duality of electron localization and covalency in lanthanide and actinide metallocenes

Unequivocal experimental evidence for carbon 2p and cerium 4f orbital mixing in cerocene, Ce(C8H8)2 is provided from carbon K-edge and Ce M5,4-edge X-ray absorption spectroscopies and corroborated with DFT and configuration interaction calculations.

Syntheses, spectroscopic, redox, and structural properties of homoleptic Iron(III/II) dithione complexes

Two sets of FeIII/II complexes, synthesized from N,N′-diisopropyl piperazine-2,3-dithione (iPr2Dt0) and N,N′-dimethyl piperazine-2,3-dithione (Me2Dt0) ligands, exhibit electronically asymmetrical ligands with metal–ligand orbital mixing.