The potential impact of GaN-based high electron mobility transistor (HEMT) with two channel layers of GaN/InAlGaN is reported. Using two-dimensional and two-carrier device simulations, we investigate the device perfor...The potential impact of GaN-based high electron mobility transistor (HEMT) with two channel layers of GaN/InAlGaN is reported. Using two-dimensional and two-carrier device simulations, we investigate the device performance focusing on the electrical potential, electron concentration, breakdown voltage and transconductance (gm). Also, the results have been compared with structure of AlGaN/GaN HEMT. Our simulation results reveal that the proposed structure increases electron concentration, breakdown voltage and transconductance;and reduces the leakage current. Also, the mole fraction of aluminum in the InAlGaN has been optimized to create the best performing device.展开更多
Objective:The roles of gonadal hormones and nitric oxide(NO) on the analgesic effects of morphine,tolerance to morphine,and their interactions have been widely investigated.In the present study,the effect of L-arginin...Objective:The roles of gonadal hormones and nitric oxide(NO) on the analgesic effects of morphine,tolerance to morphine,and their interactions have been widely investigated.In the present study,the effect of L-arginine(an NO precursor) on morphine tolerance in sham and ovariectomized(OVX) female mice was investigated.Methods:Forty mice were divided into sham and OVX groups.On the first day,a hot plate test((55±0.2) °C;cut-off 30 s) was carried out as a base record 15 min before injection of morphine(10 mg/kg,subcutaneously(s.c.)) and was repeated every 15 min after injection.The sham group was then divided into two subgroups:sham-tolerance-L-arginine(Sham-Tol-LA) and sham-tolerance-saline(Sham-Tol-Sal) which received either L-arginine 50 mg/kg(intraperitoneally(i.p.)) or saline 10 ml/kg(i.p.),respectively,three times in a day for three consecutive days.Morphine tolerance was induced in animals by injecting 30 mg/kg morphine(s.c.) three times/day for three days.This treatment was also used for OVX subgroups.On the fifth day,the hot plate test was repeated.The analgesic effect of morphine was calculated as the maximal percent effect(MPE).The results were compared using repeated measure analysis of variance(ANOVA).Results:There was no significant difference in MPE between the OVX and sham groups.The MPEs in both the Sham-Tol-Sal and OVX-Tol-Sal groups were lower than those in both the sham and OVX groups(P<0.01).The MPE in the OVX-Tol-Sal group was greater than that in the Sham-Tol-Sal group(P<0.01).The MPE in the Sham-Tol-LA group was higher than that in the Sham-Tol-Sal group(P<0.01).However,there was no significant difference between the Sham-Tol-LA and sham groups or between the OVX-Tol-LA and OVX-Tol-Sal groups.Conclusions:The results of the present study showed that repeated administration of morphine causes tolerance to the analgesic effect of morphine.L-Arginine could prevent tolerance to morphine but its effect was different in the presence of ovarian hormones.展开更多
Objective： To evaluate the effect of Nigella sativa （NS） extract on memory performance and its possible mechanisms in scopolamine （Sco）-induced spatial memory impairment model using Morris water maze test. Method...Objective： To evaluate the effect of Nigella sativa （NS） extract on memory performance and its possible mechanisms in scopolamine （Sco）-induced spatial memory impairment model using Morris water maze test. Methods： Thirty-two male Wistar rats were randomly divided into four groups. The control group received saline instead of both NS extract and Sco. The Sco group was treated by saline for two weeks, and was injected by Sco （2 mg/kg, intraperitoneally） 30 min before each trail in Morris water maze test. Sco＋NS 200 and SCO＋NS 400 groups were daily treated by 200 or 400 mg/kg of NS （intraperitoneally） for two weeks, respectively, and were finally injected by Sco 30 min before Morris water maze test. The brains of animals were removed to determine the acetylcholinesterase （ACHE） activity and oxidative stress criteria in cortical tissues. Results： Time latency and path length in the Sco group were significantly higher than in the control group （P〈0.01）, while the SCO＋NS 400 group showed a significantly shorter traveled path length and time latency compared with the Sco group （P〈0.01）. AChE activity in the cortical tissues of the Sco group was significantly higher than the control group （P〈0.01）, while AChE activity in the Sco＋NS 200 and Sco＋NS 400 groups was lower than the Sco group （P〈0.01）. Following Sco administration, malondialdehyde （MDA） concentrations were increased （P〈0.01） in comparison with the control group, while cortical total thiol content decreased （P〈0.01）. Pretreatment with extracts caused a significant elevation in cortical total thiol content （P〈0.01） and reduction in cortical MDA concentration （P〈0.01） compared with the Sco group. Conclusions： Hydro-alcoholic extract of NS prevents Sco-induced spatial memory deficits and decreases the AChE activity as well as oxidative stress of brain tissues in rats. Our results support the traditional belief about the beneficial effects of NS in nervous system. Moreover, further investigations are needed for better understanding of this protective effect.展开更多
文摘The potential impact of GaN-based high electron mobility transistor (HEMT) with two channel layers of GaN/InAlGaN is reported. Using two-dimensional and two-carrier device simulations, we investigate the device performance focusing on the electrical potential, electron concentration, breakdown voltage and transconductance (gm). Also, the results have been compared with structure of AlGaN/GaN HEMT. Our simulation results reveal that the proposed structure increases electron concentration, breakdown voltage and transconductance;and reduces the leakage current. Also, the mole fraction of aluminum in the InAlGaN has been optimized to create the best performing device.
基金Project supported by the Vice Presidency of Research of Mashhad University of Medical Sciences,Iran
文摘Objective:The roles of gonadal hormones and nitric oxide(NO) on the analgesic effects of morphine,tolerance to morphine,and their interactions have been widely investigated.In the present study,the effect of L-arginine(an NO precursor) on morphine tolerance in sham and ovariectomized(OVX) female mice was investigated.Methods:Forty mice were divided into sham and OVX groups.On the first day,a hot plate test((55±0.2) °C;cut-off 30 s) was carried out as a base record 15 min before injection of morphine(10 mg/kg,subcutaneously(s.c.)) and was repeated every 15 min after injection.The sham group was then divided into two subgroups:sham-tolerance-L-arginine(Sham-Tol-LA) and sham-tolerance-saline(Sham-Tol-Sal) which received either L-arginine 50 mg/kg(intraperitoneally(i.p.)) or saline 10 ml/kg(i.p.),respectively,three times in a day for three consecutive days.Morphine tolerance was induced in animals by injecting 30 mg/kg morphine(s.c.) three times/day for three days.This treatment was also used for OVX subgroups.On the fifth day,the hot plate test was repeated.The analgesic effect of morphine was calculated as the maximal percent effect(MPE).The results were compared using repeated measure analysis of variance(ANOVA).Results:There was no significant difference in MPE between the OVX and sham groups.The MPEs in both the Sham-Tol-Sal and OVX-Tol-Sal groups were lower than those in both the sham and OVX groups(P<0.01).The MPE in the OVX-Tol-Sal group was greater than that in the Sham-Tol-Sal group(P<0.01).The MPE in the Sham-Tol-LA group was higher than that in the Sham-Tol-Sal group(P<0.01).However,there was no significant difference between the Sham-Tol-LA and sham groups or between the OVX-Tol-LA and OVX-Tol-Sal groups.Conclusions:The results of the present study showed that repeated administration of morphine causes tolerance to the analgesic effect of morphine.L-Arginine could prevent tolerance to morphine but its effect was different in the presence of ovarian hormones.
基金the Vice Presidency of Research of Mashhad University of Medical Sciences,for financial assistance
文摘Objective： To evaluate the effect of Nigella sativa （NS） extract on memory performance and its possible mechanisms in scopolamine （Sco）-induced spatial memory impairment model using Morris water maze test. Methods： Thirty-two male Wistar rats were randomly divided into four groups. The control group received saline instead of both NS extract and Sco. The Sco group was treated by saline for two weeks, and was injected by Sco （2 mg/kg, intraperitoneally） 30 min before each trail in Morris water maze test. Sco＋NS 200 and SCO＋NS 400 groups were daily treated by 200 or 400 mg/kg of NS （intraperitoneally） for two weeks, respectively, and were finally injected by Sco 30 min before Morris water maze test. The brains of animals were removed to determine the acetylcholinesterase （ACHE） activity and oxidative stress criteria in cortical tissues. Results： Time latency and path length in the Sco group were significantly higher than in the control group （P〈0.01）, while the SCO＋NS 400 group showed a significantly shorter traveled path length and time latency compared with the Sco group （P〈0.01）. AChE activity in the cortical tissues of the Sco group was significantly higher than the control group （P〈0.01）, while AChE activity in the Sco＋NS 200 and Sco＋NS 400 groups was lower than the Sco group （P〈0.01）. Following Sco administration, malondialdehyde （MDA） concentrations were increased （P〈0.01） in comparison with the control group, while cortical total thiol content decreased （P〈0.01）. Pretreatment with extracts caused a significant elevation in cortical total thiol content （P〈0.01） and reduction in cortical MDA concentration （P〈0.01） compared with the Sco group. Conclusions： Hydro-alcoholic extract of NS prevents Sco-induced spatial memory deficits and decreases the AChE activity as well as oxidative stress of brain tissues in rats. Our results support the traditional belief about the beneficial effects of NS in nervous system. Moreover, further investigations are needed for better understanding of this protective effect.
