冲击波加载下PZT 95/5铁电陶瓷的电阻率研究

利用炸药爆炸产生的平面冲击波,研究了垂直模式冲击波加载下PbZr_0.95Ti_0.05O₃ (PZT 95/5)铁电陶瓷冲击波压缩区域的电阻率变化.在建立的模型中考虑了冲击波压缩区域的有限电阻率,计算结果表明：在压力约2.0GPa,负载短路的条件下,PZT 95/5铁电陶瓷冲击波压缩区域的电阻率从初始10⁷—10¹¹Ωcm迅速降到最小值约40Ωcm,然后基本保持在120—140Ωcm之间. 关键词： PZT 95/5铁电陶瓷 冲击波 电阻率     

PZT 95/5铁电陶瓷的冲击压缩Hugoniot特性研究

 采用一级气体炮加载装置,利用加窗VISAR技术,对极化和未极化两种状态的PZT 95/5铁电陶瓷进行了逆向冲击实验,在0.52~3.8 GPa冲击压力范围内,得到了PZT 95/5铁电陶瓷两种状态的σ-u关系。对比文献已有实验数据显示,PZT 95/5铁电陶瓷的Hugoniot曲线与初始密度值密切相关,高密度的PZT 95/5铁电陶瓷在0~3.0 GPa压力范围内的σ-u关系接近线弹性,较低压力下不同极化状态的Hugoniot数据表明,PZT 95/5铁电陶瓷发生了冲击相变。     

Green sol–gel synthesis of hydroxyapatite nanoparticles using lemon extract as capping agent and investigation of its anticancer activity against human cancer cell lines (T98, and SHSY5)

Nanotechnology and biomedical sciences open the door to a wide range of biological research topics and medical applications at the molecular and cellular levels. Biosynthesis of nanoparticles has been proposed as a cost-effective and environmentally friendly alternative to chemical and physical methods. Plant-mediated synthesis of nanoparticles is a green chemistry approach that connects nanotechnology with plants. Novel methods of ideally synthesizing NPs are thus proposed that are formed at ambient temperatures, neutral pH, low costs and in an environmentally friendly fashion. The goal of the current study is to examine the cytotoxic activity of hydroxyapatite nanoparticles in various kinds of human cancer cells and potential mechanisms at play. Hydroxyapatite nanoparticles were created by the sol–gel method using lemon extract as a capping and reducing agent to achieve environmentally friendly synthesis. The synthesized nanoparticles were characterized by XRD, SEM, FTIR, TGA, VSM and HRTEM. They were tested for cytotoxicity against T98 and SH-SY5Y, two human cancer cell lines. The synthesized nanostructures significantly caused in vitro cell death in cancer cells. The results confirmed that synthesized nanoparticles significantly decreased the percentage of cells that survived. Nevertheless, it is essential to perform more investigations to find out the exact mechanisms involved. Binding energy of Hydroxyapatite- SH-S5YS complex and Hydroxyapatite- T98 complex calculated by molecular docking. However, it is essential to perform more investigations to find the underlying mechanisms.     

Paeoniflorin improves cognitive dysfunction,restores glutamate receptors,attenuates gliosis and maintains synaptic plasticity in cadmium-intoxicated mice

Toxic metals exposed to the environment in industrial and agricultural production, such as cadmium (Cd), Plumbum (Pb) and aluminium (Al), are neurotoxic and harmful to brain functions such as learning and memory, and may contribute to neurological disease. In this study, we investigated the neuronal protective effects of Paeoniflorin (PF) in a mouse model of Cd poisoning that showed cognitive dysfunction. PF attenuated Cd-induced multi-organ damage and brain neurotoxicity, consistent with improved behavioral performances in mice. At the molecular level, Cd-induced toxicity attenuated the phosphorylation of glutamate receptors NMDAR2A, NMDAR2B, and GluR2, but increased the phosphorylation of GluR1. In addition, gliosis after Cd toxicity showed an increase in the number of IBA1 or GFAP-positive cells, which contrasted with the loss of neurons and synapses. However, PF treatment alleviated gliosis and maintained glutamate receptor and neuronal activity, as evidenced by the recovery of marker proteins MAP2, PSD95 and synaptophysin. Also, Cd-induced upregulation of CD68, a lysosomal protein that scavenges damaged cellular components in active microglia, was also restored by PF. In conclusion, PF is a potential neuroprotective natural product.