Remote Ischemia Postconditioning Mitigates Hippocampal Neuron Impairment by Modulating Cav1.2-CaMKIIα-Aromatase Signaling After Global Cerebral Ischemia in Ovariectomized Rats.

Brain-derived estrogen (BDE2) is gaining attention as an endogenous neurotransmitter. Recent research has revealed that selectively removing the aromatase gene, the pivotal enzyme responsible for BDE2 synthesis, in forebrain neurons or astrocytes can lead to synaptic loss and cognitive impairment. It is worth noting that remote ischemia post-conditioning (RIP), a non-invasive technique, has been shown to activate natural protective mechanisms against severe ischemic events.

Brain-Derived Estrogen Regulates Neurogenesis, Learning and Memory with Aging in Female Rats.

Although 17β-estradiol (E2) can be locally synthesized in the brain, whether and how brain-derived E2 (BDE2) impacts neurogenesis with aging is largely unclear. In this study, we examined the hippocampal neural stem cells, neurogenesis, and gliogenesis of 1, 3, 6, 14, and 18-month (Mon) female rats. Female forebrain neuronal knockout (FBN-ARO-KO) rats and letrozole-treated rats were also employed.

Brain-derived estrogen: a critical player in maintaining cognitive health of aged female rats, possibly involving GPR30.

Brain-derived estrogen is an endogenous neuroprotective agent, whether and how might this protective function with aging, especially postmenopausal drops in circulating estrogen, remain unclear. We herein subjected 6, 14, and 18 Mon female rats to mimic natural aging, and found that estrogen synthesis is more active in the healthy aged brain, as evidenced by the highest levels of mRNA and protein expression of aromatase, the key enzyme of E2 biosynthesis, among the three groups. Aromatase knockout in forebrain neurons (FBN-Aro-/-) impaired hippocampal and cortical neurons, and cognitive function in 18 Mon rats, compared to wild-type controls.

A novel two-degrees of freedom (2-DOF) piezo-driven positioning platform with the working stroke being over 20 cm.

Multi-degrees of freedom piezo-driven precision positioning platforms with large working strokes are demanded in many research fields. Although many multi-degrees of freedom piezo-driven positioning platforms have been proposed, few of them can achieve both large working stroke and high speed, which hinders their applications. In this study, a two-degrees of freedom piezo-driven positioning platform was proposed by stacking two identical stick-slip piezoelectric actuators.

Performance dependence of a stick-slip piezoelectric actuator on the angle between the piezoelectric stack and mover.

The angle between the piezoelectric stack (PES) and the mover would significantly affect the output performances of stick-slip piezoelectric actuators in theory; however, this issue has not been explored. Accordingly, in this paper, to investigate the effects of the angle, a stick-slip piezoelectric actuator with a changeable angle between the PES and the mover was proposed, and its structure was briefly introduced first. Then, the relationship between the angle and the parasitic motion was theoretically calculated.