Search

Background: Previous studies have indicated that selenium supplementation may be beneficial in neuroprotection against glutamate-induced cell damage, in which mitochondrial dysfunction is considered a major pathogenic feature. However, the exact mechanisms by which selenium protects against glutamate-provoked mitochondrial perturbation remain ambiguous. In this study glutamate exposed murine hippocampal neuronal HT22 cell was used as a model to investigate the underlying mechanisms of selenium-dependent protection against mitochondria damage.Results: We find that glutamate-induced cytotoxicity was associated with enhancement of superoxide production, activation of caspase-9 and -3, increases of mitochondrial fission marker and mitochondrial morphological changes. Selenium significantly resolved the glutamate-induced mitochondria structural damage, alleviated oxidative stress, decreased Apaf-1, caspases-9 and -3 contents, and altered the autophagy process as observed by a decline in the ratio of the autophagy markers LC3-I and LC3-II.Conclusion: These findings suggest that the protection of selenium against glutamate stimulated cell damage of HT22 cells is associated with amelioration of mitochondrial dynamic imbalance. [ABSTRACT FROM AUTHOR]

Structural and spectroscopic properties of Sr2ZnTeO6 (SZTO) were investigated by angle-dispersive synchrotron X-ray powder diffraction and Raman spectroscopy in a diamond anvil cell up to 31 GPa at room temperature. Although SZTO remained stable up to the highest pressure, the different pressure coefficients of the normalized axial compressibility were obtained as βab=8.16x10-3 GPa-1 and βc=7.61x10-3 GPa-1. The bulk modulus B0 was determined to be 190(1) GPa by fitting the pressure--volume data using the Birch--Murnaghan equation of state. All the observed Raman modes exhibited a broadening effect under high pressure. The vibrational band ν1 around 765 cm-1, which is associated with the Te-O stretching mode in the basal plane of the TeO6 octahedron had the largest pressure coefficient, and the Grüneisen parameters for all the observed phonon modes were also calculated and presented. These parameters could be used to measure the amount of uniaxial or biaxial strain, providing a fundamental tool for monitoring the magnitude of the shift of phonon frequencies with strains. [ABSTRACT FROM AUTHOR]

Structural and spectroscopic properties of Sr2ZnTeO6 (SZTO) were investigated by angle-dispersive synchrotron X-ray powder diffraction and Raman spectroscopy in a diamond anvil cell up to 31 GPa at room temperature. Although SZTO remained stable up to the highest pressure, the different pressure coefficients of the normalized axial compressibility were obtained as βab=8.16x10-3 GPa-1 and βc=7.61x10-3 GPa-1. The bulk modulus B0 was determined to be 190(1) GPa by fitting the pressure--volume data using the Birch--Murnaghan equation of state. All the observed Raman modes exhibited a broadening effect under high pressure. The vibrational band ν1 around 765 cm-1, which is associated with the Te-O stretching mode in the basal plane of the TeO6 octahedron had the largest pressure coefficient, and the Grüneisen parameters for all the observed phonon modes were also calculated and presented. These parameters could be used to measure the amount of uniaxial or biaxial strain, providing a fundamental tool for monitoring the magnitude of the shift of phonon frequencies with strains. [ABSTRACT FROM AUTHOR]

Hyperhomocysteinemia (HHcy) is associated with cognitive impairment and neurodegenerative diseases. The synaptic ultrastructure and the expression of hairy enhancer of split (HES) genes are involved in cognitive impairment induced by HHcy, but their precise role remains unclear. The present study aimed to measure synaptic remodeling and the expression of HES1 and HES5 in the cortex neurons of mice with HHcy to clarify their role in cognitive impairment. Mild HHcy was induced in ApoE -/- mice receiving a high-methionine diet. The correct response percentage, latency, and distance traveled in the mice with HHcy decreased compared with those of non-HHcy control mice (P < 0.05). There was no difference in the neuronal counts and the mean optical density of Nissl bodies in the frontal cortex of HHcy and non-HHcy mice. Increased apoptosis rates and numbers of autophagosomes were observed in the HHcy mice by TUNEL staining and electron microscopy, respectively, compared to those in the control group (P < 0.05). There was a significant increase in the area of postsynaptic density and size variation of synaptic vesicles in the HHcy group compared to that in the control (P < 0.05). Decreased expression of HES1 and HES5 was observed by western blotting and immunostaining in the HHcy group compared to that in the control (P < 0.05). Collectively, these results suggest that increased autophagy, apoptosis, synaptic remodeling, and downregulation of hes1 and hes5 are involved in the cognitive impairment induced by hyperhomocysteinemia., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2020. Published by Elsevier GmbH.)

High-pressure phase transition of AlN nanowires was investigated in the range of 0-33.1 GPa by in situ Raman spectrum method in diamond anvil cell (DAC). The A1 (LO) vibration mode exhibits considerably asymmetry and broadening, indicating the occurrence of wurtzite-to-rocksalt phase transition. The Raman signal of high-pressure phase can be assigned to the disorder activated Raman scattering of rocksalt AlN. After fully releasing pressure, the Raman characterization of high-pressure phase was quenched. According to the pressure dependence of phonon frequency of AlN nanowires, the difference of transiton path between AlN nanowires and bulk materials was discussed and the mode Grüneisen parameters were determined.

Objective: To determine the threshold of millimeter wave irradiation for fetal injury in mice and the mechanism of decrease of learning and memory function in their offsprings and to verify whether the millimeter wave has the non-thermal effect., Methods: Pregnant mice were irradiated by millimeter wave with frequencies of 37.4, 42.2, 53.0 and 60.0 GHz at power densities of 1, 3, 5, 8 mW/cm(2) for two hours daily from the 6th to 15th day of their gestation. Learning and memory functions of their offsprings were tested by a Y-type electric maze. c-Fos protein expression level in hippocampus of their offsprings was determined with immunohistochemistry 0, 30, 60, 90 and 120 minutes after the offsprings were trained respectively., Results: The minimal power density of millimeter wave for the decrease in learning and memory function and decrease of c-Fos protein expression level in hippocampus of their offsprings caused by 37.4, 42.2 GHz and 53.0, 60.0 GHz was 5 and 3 mW/cm(2). Severity of injury for learning and memory in offsprings caused by irradiation increased with the power density of millimeter wave. The millimeter wave did not cause increase of the body temperature of the pregnant mice., Conclusion: The threshold of millimeter wave with 37.4, 42.2 GHz, and 53.0, 60.0 GHz causing fetal injury in mice is 5 and 3 mW/cm(2) respectively. The decrease in learning and memory functions in offspring mice is related with decrease of c-Fos protein expression level in hippocampus. Millimeter wave has the non-thermal effects.