An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negati...An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negative （MNG） material is expanded from 3.53% up to 12.87% by adding split-ring resonators （SRRs） and arranging them by proposed steps. Moreover, the experimental results validate the effectiveness of bandwidth-expanding methods, which is promising for the extensive application of metamaterials in the microwave field.展开更多
Because of the tire nonlinearity and vehicle＇s parameters＇uncertainties,robust control methods based on the worst cases,such as H_∞,μsynthesis,have been widely used in active front steering control,however,in orde...Because of the tire nonlinearity and vehicle＇s parameters＇uncertainties,robust control methods based on the worst cases,such as H_∞,μsynthesis,have been widely used in active front steering control,however,in order to guarantee the stability of active front steering system（AFS）controller,the robust control is at the cost of performance so that the robust controller is a little conservative and has low performance for AFS control.In this paper,a generalized internal model robust control（GIMC）that can overcome the contradiction between performance and stability is used in the AFS control.In GIMC,the Youla parameterization is used in an improved way.And GIMC controller includes two sections：a high performance controller designed for the nominal vehicle model and a robust controller compensating the vehicle parameters＇uncertainties and some external disturbances.Simulations of double lane change（DLC）maneuver and that of braking on split-μroad are conducted to compare the performance and stability of the GIMC control,the nominal performance PID controller and the H_∞controller.Simulation results show that the high nominal performance PID controller will be unstable under some extreme situations because of large vehicle＇s parameters variations,H_∞controller is conservative so that the performance is a little low,and only the GIMC controller overcomes the contradiction between performance and robustness,which can both ensure the stability of the AFS controller and guarantee the high performance of the AFS controller.Therefore,the GIMC method proposed for AFS can overcome some disadvantages of control methods used by current AFS system,that is,can solve the instability of PID or LQP control methods and the low performance of the standard H_∞controller.展开更多
Temporal lobe epilepsy is associated with astrogliosis. Notchl signaling can induce astrogliosis in glioma. However, it remains unknown whether Notchl signaling is involved in the pathogenesis of epilepsy. This study ...Temporal lobe epilepsy is associated with astrogliosis. Notchl signaling can induce astrogliosis in glioma. However, it remains unknown whether Notchl signaling is involved in the pathogenesis of epilepsy. This study investigated the presence of Notchl, hairy and enhancer of split-l, and glial fibrillary acidic protein in the temporal neocortex and hippocampus of lithium-pilocar- pine-treated rats. The presence of Notchl and hairy and enhancer of split-1 was also explored in brain tissues of patients with intractable temporal lobe epilepsy. Quantitative electroencephalo- gram analysis and behavioral observations were used as auxiliary measures. Results revealed that the presence of Notchl, hairy and enhancer of split-l, and glial fibriUary acidic protein were en- hanced in status epilepticus and vehicle-treated spontaneous recurrent seizures rats, but remain unchanged in the following groups： control, absence of either status epilepticus or spontaneous recurrent seizures, and zileuton-treated spontaneous recurrent seizures. Compared with patient control cases, the presences of Notch1 and hairy and enhancer of split- 1 were upregulated in the temporal neocortex of patients with intractable temporal lobe epilepsy. Therefore, these results suggest that Notchl signaling may play an important role in the onset of temporal lobe epilepsy via astrogliosis. Furthermore, zileuton may be a potential therapeutic strategy for temporal lobe epilepsy by blocking Notchl signaling.展开更多
We aim to investigate the effect of transforming growth factor （TGF）-β1 on the expression of enhancer of split- and hairy-related protein-2 （SHARP-2） messenger RNA （mRNA） and its signaling pathway. In this stud...We aim to investigate the effect of transforming growth factor （TGF）-β1 on the expression of enhancer of split- and hairy-related protein-2 （SHARP-2） messenger RNA （mRNA） and its signaling pathway. In this study, several cell lines including LLC-PK1 （a porcine kidney tubular epithelial cell line）, MDCK （Madin-Darby canine kidney） and CTLL-2 （cytotoxic T-lymphocyte line） were treated with recombinant human TGF-131, and a series of experiments were carried out, involving Northern blot analysis of total RNA from these cells. Further, several specific chemical inhibitors were applied before TGF-β1 treatment to probe the signaling pathway. The results showed that TGF-β1 can significadtly up-regulate SHARP-2 mRNA expression in the LLC-PK1 cell line. The peak level of induction was found 2 h after TGF-β1 stimulation. While one phospho- inositide 3-kinases （PI-3） kinase inhibitor, LY294002, completely blocked the effect of TGF-131 on SHARP-2 mRNA expression in LLC-PK1 cells at a low concentration, other inhibitors, including PD98059, staurosporine, AG490, wortmannin, okadaic acid and rapamycin, had no effect. The effect of LY294002 was dose-dependent. We conclude that, in LLC-PK1 cells at least, TGF-β1 can effectively induce the SHARP-2 mRNA expression and that the PI-3 kinase pathway can mediate this effect.展开更多
基金Project supported partially by the National Natural Science Foundation of China (Grant Nos. 60872034 and 60971029)the New-Century Talent Program of the Education Department of China (Grant No. NCET070154)+1 种基金the National Defense Research Funding (Grant No. ZJ10DZ02111)the Hi-Tech Research and Development Program of China (Grant No. 2009AA01Z231)
文摘An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negative （MNG） material is expanded from 3.53% up to 12.87% by adding split-ring resonators （SRRs） and arranging them by proposed steps. Moreover, the experimental results validate the effectiveness of bandwidth-expanding methods, which is promising for the extensive application of metamaterials in the microwave field.
基金Supported by National Natural Science Foundation of China(Grant Nos.11072106,51375009)
文摘Because of the tire nonlinearity and vehicle＇s parameters＇uncertainties,robust control methods based on the worst cases,such as H_∞,μsynthesis,have been widely used in active front steering control,however,in order to guarantee the stability of active front steering system（AFS）controller,the robust control is at the cost of performance so that the robust controller is a little conservative and has low performance for AFS control.In this paper,a generalized internal model robust control（GIMC）that can overcome the contradiction between performance and stability is used in the AFS control.In GIMC,the Youla parameterization is used in an improved way.And GIMC controller includes two sections：a high performance controller designed for the nominal vehicle model and a robust controller compensating the vehicle parameters＇uncertainties and some external disturbances.Simulations of double lane change（DLC）maneuver and that of braking on split-μroad are conducted to compare the performance and stability of the GIMC control,the nominal performance PID controller and the H_∞controller.Simulation results show that the high nominal performance PID controller will be unstable under some extreme situations because of large vehicle＇s parameters variations,H_∞controller is conservative so that the performance is a little low,and only the GIMC controller overcomes the contradiction between performance and robustness,which can both ensure the stability of the AFS controller and guarantee the high performance of the AFS controller.Therefore,the GIMC method proposed for AFS can overcome some disadvantages of control methods used by current AFS system,that is,can solve the instability of PID or LQP control methods and the low performance of the standard H_∞controller.
基金funded by the Natural Science Foundation of Hubei Province in China,No.02.02.040458
文摘Temporal lobe epilepsy is associated with astrogliosis. Notchl signaling can induce astrogliosis in glioma. However, it remains unknown whether Notchl signaling is involved in the pathogenesis of epilepsy. This study investigated the presence of Notchl, hairy and enhancer of split-l, and glial fibrillary acidic protein in the temporal neocortex and hippocampus of lithium-pilocar- pine-treated rats. The presence of Notchl and hairy and enhancer of split-1 was also explored in brain tissues of patients with intractable temporal lobe epilepsy. Quantitative electroencephalo- gram analysis and behavioral observations were used as auxiliary measures. Results revealed that the presence of Notchl, hairy and enhancer of split-l, and glial fibriUary acidic protein were en- hanced in status epilepticus and vehicle-treated spontaneous recurrent seizures rats, but remain unchanged in the following groups： control, absence of either status epilepticus or spontaneous recurrent seizures, and zileuton-treated spontaneous recurrent seizures. Compared with patient control cases, the presences of Notch1 and hairy and enhancer of split- 1 were upregulated in the temporal neocortex of patients with intractable temporal lobe epilepsy. Therefore, these results suggest that Notchl signaling may play an important role in the onset of temporal lobe epilepsy via astrogliosis. Furthermore, zileuton may be a potential therapeutic strategy for temporal lobe epilepsy by blocking Notchl signaling.
基金supported by the National Natural Science Foundation of China (Nos. 30471641 and 30872389)the Natural Science Foundation of Zhejiang Province, China (No. Y207088)
文摘We aim to investigate the effect of transforming growth factor （TGF）-β1 on the expression of enhancer of split- and hairy-related protein-2 （SHARP-2） messenger RNA （mRNA） and its signaling pathway. In this study, several cell lines including LLC-PK1 （a porcine kidney tubular epithelial cell line）, MDCK （Madin-Darby canine kidney） and CTLL-2 （cytotoxic T-lymphocyte line） were treated with recombinant human TGF-131, and a series of experiments were carried out, involving Northern blot analysis of total RNA from these cells. Further, several specific chemical inhibitors were applied before TGF-β1 treatment to probe the signaling pathway. The results showed that TGF-β1 can significadtly up-regulate SHARP-2 mRNA expression in the LLC-PK1 cell line. The peak level of induction was found 2 h after TGF-β1 stimulation. While one phospho- inositide 3-kinases （PI-3） kinase inhibitor, LY294002, completely blocked the effect of TGF-131 on SHARP-2 mRNA expression in LLC-PK1 cells at a low concentration, other inhibitors, including PD98059, staurosporine, AG490, wortmannin, okadaic acid and rapamycin, had no effect. The effect of LY294002 was dose-dependent. We conclude that, in LLC-PK1 cells at least, TGF-β1 can effectively induce the SHARP-2 mRNA expression and that the PI-3 kinase pathway can mediate this effect.
