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A previous study demonstrated that middle-aged (5-6 months of age) senescence-accelerated mouse prone 8 (SAMP8) mice can be used as animal models of mild cognitive impairment (MCI). An enriched environment (EE) can mitigate cognitive decline and decrease the pathological changes associated with various neurodegenerative diseases. In the present study, the learning-memory abilities of SAMP8 mice during the MCI phase (5 months of age) was evaluated and neuropathological changes in the hippocampus were examined after the mice were exposed to an EE for 60 days. In the Morris water maze test, EE-exposed mice demonstrated significantly decreased escape latency and increased time spent in the target quadrant and number of platform crossings compared with control mice. Terminal deoxynucleotidyl transferase dUTP nick end labeling and Nissl staining showed that EE-exposed mice had reduced neuronal apoptosis and increased number of surviving neurons compared with control mice. Golgi staining, transmission electron microscopy, and immunohistochemical staining demonstrated that EE-exposed mice exhibited increased dendritic spine densities among secondary and tertiary apical dendrites; increases in synaptic numerical density, synaptic surface density, and expression of synaptophysin; and reduced deposition of amyloid-β (Aβ) and expression of amyloid-precursor protein (APP) in the hippocampal CA1 region compared with control mice. These results demonstrate that EE exposure effectively decreases neuronal loss and regulates neuronal synaptic plasticity by reducing the expression of APP and the deposition of Aβ in the hippocampal CA1 region, thereby mitigating cognitive decline in SAMP8 mice during the MCI phase and delaying the progression from MCI to Alzheimer's disease.

Multi-group orthogonal experiments cooperating MATLAB stimulation were employed to synthesise antimony-doped tin oxide (ATO) (Sb–SnO2)-doped silica (ATO/SiO2) composite powder with high conductivity and dispersivity analysis. Results suggested that the resistivity ranged from 3.9 to 300 Ω cm while the nano-silica doping amount ranged from 0 to 1.5% (mass ratio) under the best parameters of Sb-doped content of 9.5 mol%, 3 precursor wash times, calcination temperature of 750°C, gelling reaction temperature of 45°C and calcination time of 2 h. Both the ATO and ATO/SiO2 particles were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscope studies to prove that the addition of silica could not only increase the specific surface area and resistivity of particles, but also reduce the agglomeration of particles. The relationship between conductivity and dispersion of composite powder (Sb–SnO2−SiO2) dominated by different nano-silica content could be simulated by the ‘logistic function model’, which has important guiding significance for the preparation of composite powders with prominent characteristics.

A high precision superconducting levitation system for gravity measurement has been developed, which used the levitation of a superconducting sphere by the magnetic field of two superconducting coils. The magnetic levitation is designed to provide independent adjustment of the levitating force and the force gradient. A Gifford-McMahon (GM) cryocooler is employed to cool down the system. This paper reviews the construction and operating characteristics of the system. The test results show that the earth tide signal was detected by the system.

A new approach is proposed for the determination of gravity tide parameters. Three pairs of compactly supported wavelet filters are introduced in the approach. They can efficiently extract the objective tides from the gravity observation series. The new approach guarantees a direct and precise analysis on the tidal gravity records of any sampling length. The new approach is applied to the harmonic analysis on Wuhan superconducting gravimeter records. The results clearly show the resonant effects of the Earth Nearly Diurnal Free Wobble (NDFW).

In this paper, the calibration factor of the superconducting gravimeter 057 (SG057) at the Lhasa station is accurately determined for the first time with a frequency-domain approach and the data recorded by the LaCoste Romberg Earth Tides No. 20 (LCR-ET20) gravimeter which is installed nearby SG057. The advantage of the frequency-domain approach is that it eliminates the influence of different gravimeter drifts on the determination of the calibration factor. The determined calibration factor of SG057 is (-77.7358 ± 0.0409) × 10^(-8) m s^(-2) V^(-1), and the relative accuracy is about 0.5 per mille. The newly determined calibration factor has been calculated with the Wuhan international tidal gravity reference values (ITGRVs) based on the data recorded by LCR-ET20 at the Wuhan station before it was installed at the Lhasa station. A high-precision synthesized gravity tide is achieved at the Lhasa station with accurate tidal parameters and theoretical tidal parameters for the long tidal waves from the Dehant-Defraigne-Wahr (DDW) earth tide model. The synthesized gravity tide can be used for tidal gravity corrections of future gravity measurements in the Tibetan area. The linear gravimeter drift of SG057 is estimated by gravity records without the effects of land uplift, atmosphere and polar motion yielding a rate of 6.8 × 10^(-8) m s^(-2) yr^(-1).