The distribution of phospholipids across the inner membrane (IM) of Gram-negative bacteria is unknown. We demonstrate that the IMs of Escherichia coli and Yersinia pseudotuberculosis are asymmetric, with a 75%/25% (cytoplasmic/periplasmic leaflet) distribution of phosphatidylethanolamine (PE) in rod-shaped cells and an opposite distribution in E. coli filamentous cells. In initially filamentous PE-lacking E. coli cells, nascent PE appears first in the periplasmic leaflet. As the total PE content increases from nearly zero to 75%, cells progressively adopt a rod shape and PE appears in the cytoplasmic leaflet of the IM. The redistribution of PE influences the distribution of the other lipids between the leaflets. This correlates with the tendency of PE and cardiolipin to regulate antagonistically lipid order of the bilayer. The results suggest that PE asymmetry is metabolically controlled to balance temporally the net rates of synthesis and translocation, satisfy envelope growth capacity, and adjust bilayer chemical and physical properties.

Co-doped Ce³⁺, Cr³⁺and Pr³⁺yttrium–aluminium–gallium garnet powders of various sizes were obtained by co-precipitation method. The microstructure and morphology were investigated by XRPD, TEM and gas porosimetry. The luminescence properties were studied by excitation and emission spectra, quantum yield and decay times. Thermoluminescence measurements were performed to evaluate the activation energy, traps redistribution and frequency factor. Limitation in the energy transfer between dopant ions in the small particles, traps depth and surface defects were considered and investigated as responsible for the quenching of persistent luminescence. The phosphors annealed at 1100 °C show the optimal persistent luminescence and nano-particle size.

In order to obtain Gd_2.97Pr_0.03Ga₃Al₂O₁₂ powders with different crystallite sizes, a modified Pechini (sol–gel) method was used. Powders were then used for the preparation of ceramics by a high-pressure low-temperature sintering method. The impact of crystallite size and pressure applied during the sintering procedure on conventional and persistent luminescence was investigated and analyzed. It was found that the emission color is strictly dependent on the crystallite size, as such phenomenon may be used in the field of advanced anti-counterfeiting. The spectroscopic properties of Gd_2.97Pr_0.03Ga₃Al₂O₁₂ were characterized by means of photoluminescence measurements. The kinetics of luminescence were measured in order to analyze the energy transfer between ³P₀ and ¹D₂ excited states that also take an active role in the persistent luminescence process. It was found that an increase in the crystallite size led to a higher energy transfer from the ³P₀ to ¹D₂ level and a change in the emission color. As such, it was studied for potential application in ratiometric optical thermometry. The effect was also investigated in terms of persistent luminescence. It was also found that the sintering pressure causes changes in the crystallographic parameters of the powders and, in consequence, has a great impact on the optical properties of ceramics. The conducted research gives insights into the mechanism of persistent luminescence and expands the application field of optical storage materials.