Rare earth (RE) doped Ca9La(PO4)(5)(SiO4)Cl-2 phosphors were synthesized using the solid-state reaction method and characterized through XRD, SEM, EDS, FTIR, and photoluminescence (PL). XRD confirmed the formation of a hexagonal structure Ca9La(PO4)(5)(SiO4)Cl-2 compound with space group P63/m. SEM analysis revealed agglomerated and non-uniform particles ranging from a few mu m. PL analysis indicated that the Ca9La(PO4)(5)(SiO4)Cl-2 doped with Eu3+, Eu2+, and Sm3+ can be effectively excited using a near-ultraviolet (n-UV) LED chip, emitting light in the red (612 nm), blue (454 nm), and orange-red (602 nm) regions, respectively. Additionally, energy transfer processes from Ce3+ to Eu2+ and Ce3+ to Sm3+ were investigated. The findings suggest that these phosphors can have promising applications in LED technology, particularly as candidates for specialized plant growth LEDs and white LED (W-LED) applications.
Alzheimer's disease (AD) is a prevalent neurodegenerative disorder closely associated with neurotoxic aggregation of amyloid-beta (A beta) peptides, yet the subcellular and single-cell molecular mechanisms underlying A beta-induced injury remain incompletely understood. In this work, HT22 cells were exposed to varying concentrations of A beta 25-35 to investigate the neurotoxic effects and cellular injury induced by the peptide. Synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectroscopy, a label-free technique combined with multivariate statistical analysis was used to characterize A beta 25-35-induced biomolecular alterations at the single-cell scale. Euclidean distances derived from single-cell spectra were further computed to quantitatively assess intercellular biomolecular heterogeneity. Spectral analysis revealed obvious changes in lipid structure and composition in all A beta 25-35-exposed cell groups. An increased beta-sheet/alpha-helix ratio and a decreased nucleic acid-to-protein ratio were also identified, indicating alterations in protein conformation and nucleic acid content. Moreover, cells treated with varying A beta 25-35 exhibited distinct degrees of intercellular heterogeneity. These findings provide spectroscopic evidence for the neurotoxic effects of A beta on HT22 cells, and demonstrate the single-cell SR-FTIR spectroscopy as a sensitive tool for probing biomolecular changes at cellular level.
