The study demonstrates the mechanism of pterostilbene alleviating cerebral ischemia and reperfusion injury in rats may associate with the inhibition of ROS/NF-κB-mediated inflammatory pathway.
Scope
In the present study, effect of pterostilbene on β‐amyloid 1‐42 (Aβ1‐42) induced cognitive impairment in mice is investigated and explored its possible mechanism of action.
Methods and results
The behavior results show that pterostilbene alleviated Aβ1‐42‐induces cognitive dysfunction assessed using the Y‐maze test, novel object recognition task, Morris water maze test, and passive avoidance test. Pterostilbene alleviates neuron loss and accumulation of reactive oxygen species in Aβ1‐42 treated mouse brain. Additionally, pterostilbene promotes nuclear factor‐E2 p45‐related factor 2 (Nrf2) nuclear translocation and enhance the transcription and expression of antioxidant genes such as heme oxygenase‐1 and superoxide dismutase both in vivo and in vitro. Nrf2 inhibitor ML385 reverses the antioxidant function of pterostilbene in SH‐SY5Y cells. Nrf2 is the master regulator of oxidative homeostasis and can be activated by substrate adaptor sequestosome‐1 (also named p62). Pterostilbene promotes the binding of Kelch‐like ECH‐associated protein 1 and p62, which enhanced activation of Nrf2.
Conclusion
The present study reports that pterostilbene alleviated Aβ1‐42‐induces cognitive dysfunction in mice. The mechanism of pterostilbene can be associated to the inhibition of oxidative stress through the Nrf2 signaling pathway.
During the dead-time interval for a phase-shifted full-bridge (PSFB) converter, switches can achieve zero-voltage switching (ZVS) operation by using the energy stored in the transformer leakage inductance to discharge or charge the output capacitance of the switches. The value of dead-time has a great effect on ZVS range so it is a key parameter that needs to be optimised during designing the converter. This study develops theoretical analysis to estimate the dead-time as a function of load current for PSFB converter. The equivalent circuits of PSFB converter during the deadtime interval with considering magnetising inductance are mainly analysed in this study. Compared with previous analyses, the influences of dead-time on ZVS range and efficiency are discussed in detail. The analysis results show that the magnetising inductance of transformer can ensure ZVS over a wide range of load conditions, especially under discontinued current mode operation, without a penalty on the heavy-load efficiency. By adjusting the dead-time dynamically, both conduction and switching losses can be reduced. A 1 kW prototype is implemented and experimental results are consistent with the theoretical analysis.
The pharmaceutical tablet manufacturing process (PTMP) via wet granulation holds a critical position in pharmaceutical industry. The interest in integrating mechanistic process modeling into the pharmaceutical development has been increased because simulation model is a prerequisite for process design, analysis, control, and optimization. So the simulation modeling for PTMP via wet granulation is very necessary and significant. This study aims at proposing a simulation modeling framework for PTMP via spray fluidized bed granulation (SFBG), which is one of the most widely used wet granulation techniques in pharmaceutical industry. For SFBG, a simulation model that simultaneously involves the influences of operating variables and material attributes on average particle size (APS) is firstly developed, and then a drying model to determine the particle moisture content is introduced to be coupled with the established model predicting APS. For PTMP, considering the important effect of porosity on tablet qualities, a model describing the changes in tablet porosity is developed based on a promoted form of the Heckel equation, and then several recognized models that are all related to porosity are introduced or constructed to calculate important tablet quality indexes. The feasibility and effectiveness of the developed simulation models are validated by performing a computational experimental study to explore the scientific understanding of process and process quality control.
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