Purely organic materials with room-temperature phosphorescence (RTP) are currently under intense investigation because of their potential applications in sensing, imaging, and displaying. Inspired by certain organometallic systems, where ligand-localized phosphorescence ((3) π-π*) is mediated by ligand-to-metal or metal-to-ligand charge transfer (CT) states, we now show that donor-to-acceptor CT states from the same organic molecule can also mediate π-localized RTP. In the model system of N-substituted naphthalimides (NNIs), the relatively large energy gap between the NNI-localized (1) π-π* and (3) π-π* states of the aromatic ring can be bridged by intramolecular CT states when the NNI is chemically modified with an electron donor. These NNI-based RTP materials can be easily conjugated to both synthetic and natural macromolecules, which can be used for RTP microscopy.
The refinement of XRD patterns only
provides the average structure
parameters for the alloying materials because of the symmetric protection.
Raman vibrational modes can append the detailed information about
the bond length and structure. The refinements of XRD patterns for
Bi alloying Cs2AgInCl6 revealed the strong structure
distortion with the enlarged octahedron of In(Bi)Cl6 and
the contracted octahedron of AgCl6 with the increasing
Bi. Raman spectra supported the expanded octahedron of InCl6 and the reduced octahedron of AgCl6 but identified the
anomalous shortening bond length of Bi–Cl with the increasing
Bi. These distorting octahedrons break parity forbidden transition,
modify Huang–Rhys factor, and result in the maximum values
at 30% Bi alloying and the same variation trend for both photoluminescence
and Huang–Rhys factor with the increasing Bi alloying.
Although a growing body of evidence supports the importance of the Wnt/β-catenin signaling pathway and oxidative stress in the pathogenesis of autism, it is unclear whether a relationship exists between the Wnt/β-catenin pathway and oxidative homeostasis. The present study examines the effects of sulindac, a small molecule inhibitor of the Wnt/β-catenin signaling pathway, on the oxidative status of rats that are prenatally exposed to valproic acid (VPA), which is used in an animal model of autism. Our data show that sulindac treatment downregulated the canonical Wnt/β-catenin signaling pathway by enhancing the expression of Glycogen Synthase Kinase 3β and attenuating the expression of β-catenin in comparison to levels in VPA-treated rats. Concomitantly, a marker of lipid peroxidation, 4-hydroxynonenal, was reduced as well. Sulindac treatment ameliorated the pain threshold, repetitive/stereotypic activity, learning and memory abilities and behavioral abnormalities of rats in our autism model. Our working model suggests that the upregulation of the Wnt/β-catenin signaling pathway induced by VPA administration during early pregnancy produces an imbalance of oxidative homeostasis that facilitates susceptibility to autism. This information may be instrumental in designing appropriate therapeutic regimens with small molecule inhibitors of the Wnt/β-catenin pathway for the treatment of autism-like behavioral phenotypes.
Amyloid plaques and neurofibrillary tangles are pathologic hallmarks of Alzheimer's disease (AD). Endoplasmic reticulum (ER) stress has been implicated in the loss of neurons in AD. The phosphatase and tensin homolog deleted on chromosome ten (PTEN) plays an important role in regulating neuronal survival processes. However, the direct effects of the PTEN on ER stress and apoptosis in AD have not been elucidated. In this study, we demonstrate that the expression of PTEN and ER stress related proteins, GRP78 and CHOP, increased in APP/PS1 transgenic AD mice compared with WT mice. A PTEN inhibitor, dipotassium bisperoxo-(5-hydroxypyridine-2-carboxyl)-oxovanadate (bpv) could decrease apoptosis, induce AKT phosphorylation and inhibit the ER stress response proteins in hippocampus in APP/PS1 transgenic AD model mice. Furthermore, treatment with the specific PI3K inhibitor, LY294002, significantly blocked the anti-apoptotic effects of bpv in AD mice. The expression in GRP78, CHOP and apoptosis levels by bpv was reversed after PI3K inhibitor treatment. Taken together, our results indicate that the neuroprotective role of bpv involves the suppression of ER stress via the activation of the PI3K/AKT signalling pathways in APP/PS1 transgenic AD model mice.
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