32 research outputs found
Charge Carrier Recombination Dynamics in MAPb(Br<sub><i>x</i></sub>Cl<sub>1ā<i>x</i></sub>)<sub>3</sub> Single Crystals
Understanding carrier recombination processes in MAPbĀ(BrxCl1āx)3 crystals is essential for their photoelectrical applications.
In
this work, carrier recombination dynamics in MAPbĀ(BrxCl1āx)3 single
crystals were studied by steady-state photoluminescence (PL), time-resolved
photoluminescence (TRPL), and time-resolved microwave photoconductivity
(TRMC). By comparing TRPL and TRMC, we find TRPL of MAPbĀ(BrxCl1āx)3 (x < 0.98) single crystals is dominated by a
hole trapping process while the long-lived component of TRMC is dominated
by an electron trapping process. We also find both electron and hole
trapping rates of MAPbĀ(BrxCl1āx)3 (x < 0.98) crystals
decrease with an increase in Br content. A temperature-dependent PL
study shows there are shallow trap states besides the deep level trap
states in the MAPbĀ(Br0.82Cl0.18)3 crystal. The activation energy for holes in shallow trap states
detrapped into the valence band is ā¼0.1 eV, while the activation
energy for free holes to be trapped into deep trap states is ā¼0.4
eV. This work provides insight into carrier recombination processes
in MAPbĀ(BrxCl1āx)3 single crystals
Expression of ERK, JNK, p38, MKP-1 and MKP-3 in the hippocampus in repeated morphine (nā=ā6) or saline (nā=ā6) treated mice.
<p>Western blots were performed on a separate cohort of animals which did not undergo behavioral testing. Ratios of the phospho-protein relative to total protein levels were analyzed. Data are expressed as the mean Ā± SEM relative to saline controls that were set as 1. The Ī²-actin was utilized as a loading control. *p<0.05; **p<0.01; ***p<0.0001 compared with the saline group.</p
Differential Regulation of MAPK Phosphorylation in the Dorsal Hippocampus in Response to Prolonged Morphine Withdrawal-Induced Depressive-Like Symptoms in Mice
<div><p>Depression is one of the most frequent neuropsychiatric comorbidities associated with opiate addiction. Mitogen activated protein kinase (MAPK) and MAPK phosphatase (MKP) are involved in drug addiction and depression. However, the potential role of MAPK and MKP in depression caused by morphine withdrawal remains unclear. We utilized a mouse model of repeated morphine administration to examine the molecular mechanisms that contribute to prolonged withdrawal induced depressive-like behaviors. Depressive-like behaviors were significant at 1 week after withdrawal and worsened over time. Phospho-ERK (extracellular signal-regulated protein kinase) was decreased and MKP-1 was elevated in the hippocampus, and JNK (c-Jun N-terminal protein kinase), p38 (p38 protein kinase) and MKP-3 were unaffected. A pharmacological blockade of MKP-1 by intra-hippocampal sanguinarine (SA) infusion prevented the development of depressive-like behaviors and resulted in relatively normal levels of MKP-1 and phospho-ERK after withdrawal. Our findings support the association between hippocampal MAPK phosphorylation and prolonged morphine withdrawal-induced depression, and emphasize the MKP-1 as an negative regulator of the ERK phosphorylation that contributes to depression.</p></div
Body weight change and withdrawal scores in the experiment 1.
<p>(A) Timeline of the experiment 1. The duration of each stage (number of days) is shown under the axis. Black triangles indicate escalating doses of morphine or saline injected twice daily for 8 consecutive days. Dash arrows indicate the observation of the withdrawal behaviors at different time points after the last morphine administration. Solid black arrows indicate the behavioral testing at two withdrawal time points during the study. āSac.ā indicates that mice were sacrificed. (B) The influence of repeated morphine injection and prolonged withdrawal on body weight during the experimental period. (C) Withdrawal scores following the last dose of morphine injection. The data are expressed as the mean Ā± SEM. Significance relative to control is indicated by *p<0.05; **p<0.01; ***p<0.0001.</p
Intra-hippocampal SA infusion alleviates depressive-like behaviors during the morphine withdrawal period.
<p>Four behavioral tests were analyzed in mice of different treatment combinations after 1 or 4 weeks of morphine withdrawal: (A) Locomotor activity, (B) time spent in the center of the arena, (C) Social interaction time and (D) immobility in tail suspension test. The data are expressed as the mean Ā± SEM. Significance between morphine and saline control is indicated as *p<0.05; **p<0.01; ***p<0.0001. Comparison between SA and DMSO treatment is indicated by <sup>#</sup>p<0.05; <sup>##</sup>p<0.01.</p