A simple PI controller tuning method for large dead-time processes is presented. First, a first-order plus dead-time model is identified on the basis of relay feedback experiments, which Nyquist curve is very close to...A simple PI controller tuning method for large dead-time processes is presented. First, a first-order plus dead-time model is identified on the basis of relay feedback experiments, which Nyquist curve is very close to that of large dead-time processes over a wide frequency range. With the model available, PI controller is designed with a new robust specification. Simulation examples show the effectiveness and feasibility of the presented PI tuning method for large dead-time processes.展开更多
OBJECTIVE Erzhi pills is a clas⁃sic prescription of Chinese medicine originated from Fu Shou Jing Fang in Ming dynasty,with the effects of nourishing kidney-Yin and hemosta⁃sis,black hair,strengthening muscles and bon...OBJECTIVE Erzhi pills is a clas⁃sic prescription of Chinese medicine originated from Fu Shou Jing Fang in Ming dynasty,with the effects of nourishing kidney-Yin and hemosta⁃sis,black hair,strengthening muscles and bones.As a classical prescription for nourishing kidney-Yin,Erzhi pills has been used to treat senile dementia in China for many years.Herein,our study aimed to investigate the protective effects of Erzhi pills in rat models of Alzheimer disease(AD)induced by ovariectomy as well as D-galactose and Aβ1-40 injection and to explore its potential mechanism.METHODS The model of AD rats was established by ovariectomy com⁃bined with D-galactose and Aβ1-40 injection.Ovariectomized rats were randomly divided into four groups:model group,estradiol valerate(0.80 mg·kg-1)group,Erzhi pills high(1.50 mg·kg-1)and low(0.75 mg·kg-1)doses group.In addition,rats of sham operation were selected as the sham operated group.Except for the sham oper⁃ated group,rats were injected intraperitoneally with D-galactose(100 mg·kg-1 per day,for 49 d)on the 8th day,then they were given intracerebro⁃ventricular injection of Aβ1-40(10μg per rat,1 g·L-1)on the 36th day,while the corresponding drugs were given by gastrointestinal administra⁃tion on the 22nd day.In our study,Morris water maze test was used to evaluate the learning and memory abilities,while ELISA kit was used to an⁃alyze serum estrogen level.The morphology of hippocampal neuron cells was observed by HE staining,and Nissl staining was utilized to ob⁃serve the Nissl body in cytoplasm.Then,the ex⁃pression of ERβpositive cells and hippocampal Aβ1-40 and p-Tau404 proteins was determined by immunohistochemistry.In order to further explore the molecular mechanism of Erzhi pills preven⁃tion and treatment of AD,proteomics was used to find potential targets and related pathways,Western blotting was used to verify the expres⁃sion of candidate differential protein.According to the results of proteomics in our experiment,Western blotting was used to detect the protein expression of PI3K,Akt,Bcl-2,Bcl-xl,Bad,14-3-3 and GSK3β.RESULTS The escape latency was significantly shortened,the number of crossing platform was increased,the neuron arrange⁃ment was more orderly and with less nuclear pycnosis in rats of Erzhi pills groups compared to the model group.In rats treated with Erzhi pills,the number of neurons,Nissl bodies,the estro⁃gen levels and ERβpositive cells were increased,while the number of Aβ1-40 and p-Tau404 positive cells was significantly decreased.Proteomics found that there were more than one hundred differentially expressed proteins of rats treated with Erzhi pills,which were involved in 48 signal⁃ing pathways.Among these proteins,five of them were involved in the PI3K/Akt signal path⁃way.As the down-stream protein of PI3K/Akt sig⁃naling pathway,the content of 14-3-3 protein was significantly increased.Western blotting analysis showed that the expression of p-GSK3β/GSK3βand Bad was decreased,while that of p-Akt/Akt,p-PI3K/PI3K,14-3-3,Bcl-xl and Bcl-2 was up-regulated in rats from the Erzhi pills groups compared with the model group.CON⁃CLUSION Erzhi pills can improve estrogen levels,alter proteomics expression of the hippocampus and activate PI3K/Akt pathway in AD rats,reduce Aβaggregation,inhibit the hyperphos⁃phorylation of Tau protein,maintain the morphol⁃ogy of hippocampal neurons and decrease the apoptosis of hippocampal neurons,thereby improving the learning and memory abilities of ovariectomized AD rats induced by D-galactose and Aβ1-40 injection.This study may provide an experimental basis for the clinical treatment of Erzhi pills.展开更多
基金Supported by the Key Program of National Natural Science Foundation of China （60634020）, Doctoral Program Foundation of Ministry of Education of China （20050533028, 20070533132）, Natural Science Foundation of Hunan Province （06J35145）, and Program for New Century Excellent Talents in University （NCET-07-0867）
基金This project was support by the National "863" High-Tech Research and Development Foundation (2001AA413130).
文摘A simple PI controller tuning method for large dead-time processes is presented. First, a first-order plus dead-time model is identified on the basis of relay feedback experiments, which Nyquist curve is very close to that of large dead-time processes over a wide frequency range. With the model available, PI controller is designed with a new robust specification. Simulation examples show the effectiveness and feasibility of the presented PI tuning method for large dead-time processes.
文摘OBJECTIVE Erzhi pills is a clas⁃sic prescription of Chinese medicine originated from Fu Shou Jing Fang in Ming dynasty,with the effects of nourishing kidney-Yin and hemosta⁃sis,black hair,strengthening muscles and bones.As a classical prescription for nourishing kidney-Yin,Erzhi pills has been used to treat senile dementia in China for many years.Herein,our study aimed to investigate the protective effects of Erzhi pills in rat models of Alzheimer disease(AD)induced by ovariectomy as well as D-galactose and Aβ1-40 injection and to explore its potential mechanism.METHODS The model of AD rats was established by ovariectomy com⁃bined with D-galactose and Aβ1-40 injection.Ovariectomized rats were randomly divided into four groups:model group,estradiol valerate(0.80 mg·kg-1)group,Erzhi pills high(1.50 mg·kg-1)and low(0.75 mg·kg-1)doses group.In addition,rats of sham operation were selected as the sham operated group.Except for the sham oper⁃ated group,rats were injected intraperitoneally with D-galactose(100 mg·kg-1 per day,for 49 d)on the 8th day,then they were given intracerebro⁃ventricular injection of Aβ1-40(10μg per rat,1 g·L-1)on the 36th day,while the corresponding drugs were given by gastrointestinal administra⁃tion on the 22nd day.In our study,Morris water maze test was used to evaluate the learning and memory abilities,while ELISA kit was used to an⁃alyze serum estrogen level.The morphology of hippocampal neuron cells was observed by HE staining,and Nissl staining was utilized to ob⁃serve the Nissl body in cytoplasm.Then,the ex⁃pression of ERβpositive cells and hippocampal Aβ1-40 and p-Tau404 proteins was determined by immunohistochemistry.In order to further explore the molecular mechanism of Erzhi pills preven⁃tion and treatment of AD,proteomics was used to find potential targets and related pathways,Western blotting was used to verify the expres⁃sion of candidate differential protein.According to the results of proteomics in our experiment,Western blotting was used to detect the protein expression of PI3K,Akt,Bcl-2,Bcl-xl,Bad,14-3-3 and GSK3β.RESULTS The escape latency was significantly shortened,the number of crossing platform was increased,the neuron arrange⁃ment was more orderly and with less nuclear pycnosis in rats of Erzhi pills groups compared to the model group.In rats treated with Erzhi pills,the number of neurons,Nissl bodies,the estro⁃gen levels and ERβpositive cells were increased,while the number of Aβ1-40 and p-Tau404 positive cells was significantly decreased.Proteomics found that there were more than one hundred differentially expressed proteins of rats treated with Erzhi pills,which were involved in 48 signal⁃ing pathways.Among these proteins,five of them were involved in the PI3K/Akt signal path⁃way.As the down-stream protein of PI3K/Akt sig⁃naling pathway,the content of 14-3-3 protein was significantly increased.Western blotting analysis showed that the expression of p-GSK3β/GSK3βand Bad was decreased,while that of p-Akt/Akt,p-PI3K/PI3K,14-3-3,Bcl-xl and Bcl-2 was up-regulated in rats from the Erzhi pills groups compared with the model group.CON⁃CLUSION Erzhi pills can improve estrogen levels,alter proteomics expression of the hippocampus and activate PI3K/Akt pathway in AD rats,reduce Aβaggregation,inhibit the hyperphos⁃phorylation of Tau protein,maintain the morphol⁃ogy of hippocampal neurons and decrease the apoptosis of hippocampal neurons,thereby improving the learning and memory abilities of ovariectomized AD rats induced by D-galactose and Aβ1-40 injection.This study may provide an experimental basis for the clinical treatment of Erzhi pills.
