Memory deficits with aging are related to the neurodegeneration in the brain, including a reduction in arginine vasopressin(AVP) in the brain of patients with Alzheimer’s disease(AD). AVP(4-8), different from its pre...Memory deficits with aging are related to the neurodegeneration in the brain, including a reduction in arginine vasopressin(AVP) in the brain of patients with Alzheimer’s disease(AD). AVP(4-8), different from its precursor AVP, plays memory enhancement roles in the CNS without peripheral side-effects. However, it is not clear whether AVP(4-8) can improve cognitive behaviors and synaptic plasticity in the APP/PS1 mouse model of AD. Here, we investigated for the first time the neuroprotective effects of AVP(4-8) on memory behaviors and in vivo long-term potentiation(LTP) in APP/PS1-AD mice.The results showed that:(1) APP/PS1-AD mice had lower spontaneous alternation in the Y-maze than wild-type(WT) mice, and this was significantly reversed by AVP(4-8);(2) the prolonged escape latency of APP/PS1-AD mice in the Morris water maze was significantly decreased by AVP(4-8), and the decreased swimming time in target quadrant recovered significantly after AVP(4-8) treatment;(3) in vivo hippocampal LTP induced by high-frequency stimulation had a significant deficit in the AD mice, and this was partly rescued by AVP(4-8);(4) AVP(4-8)significantly up-regulated the expression levels of postsynaptic density 95(PSD95) and nerve growth factor(NGF)in the hippocampus of AD mice. These results reveal the beneficial effects of AVP(4-8) in APP/PS1-AD mice,showing that the intranasal administration of AVP(4-8)effectively improved the working memory and long-term spatial memory of APP/PS1-AD mice, which may be associated with the elevation of PSD95 and NGF levels in the brain and the maintenance of hippocampal synaptic plasticity.展开更多
Cr-Ni-Mo-V steam-turbine rotors have been widely used as key components in power plants. In this study, a coupled thermomechano-metallurgical model was proposed to simulate the phase transformation and transformation-...Cr-Ni-Mo-V steam-turbine rotors have been widely used as key components in power plants. In this study, a coupled thermomechano-metallurgical model was proposed to simulate the phase transformation and transformation-induced plasticity (TRIP) of a 30Cr2Ni4MoV steam-turbine rotor during a water-quenching process, which was solved using a user defined material mechanical behavior (UMAT) subroutine in ABAQUS. The thermal dilation, heat generation from plastic work, transformation latent heat, phase transformation kinetics, and TRIP were considered in the model. The thermomechanical portion of the model was used to predict the evolution of temperature, strain, and residual stress in the rotor. The phase transformation that occurred during the quenching process was considered. Constitutive models of phase transformations (austenite to pearlite, austenite to bainite, and austenite to martensite) and TRIP were developed. Experimental data were adopted and compared with the predicted results to verify the accuracy of the model. This demonstrates that the model is reliable and accurate. Then, the model was utilized to predict the temperature variation, dimensional change, minimum austenitization time, residual stress, TRIP, and volume fractions of each phase. It is concluded that this model can be a useful computational tool in the design of heat-treatment routines of steam-turbine rotors.展开更多
基金the National Natural Science Foundation of China(31471080)the Scientific Program for“Sanjin Scholars”of Shanxi Province,Shanxi“1331 Project”Key Subjects Construction(1331KSC)Science Foundation for Excellent Young Scholars of Shanxi Province,China(201801D211005)。
文摘Memory deficits with aging are related to the neurodegeneration in the brain, including a reduction in arginine vasopressin(AVP) in the brain of patients with Alzheimer’s disease(AD). AVP(4-8), different from its precursor AVP, plays memory enhancement roles in the CNS without peripheral side-effects. However, it is not clear whether AVP(4-8) can improve cognitive behaviors and synaptic plasticity in the APP/PS1 mouse model of AD. Here, we investigated for the first time the neuroprotective effects of AVP(4-8) on memory behaviors and in vivo long-term potentiation(LTP) in APP/PS1-AD mice.The results showed that:(1) APP/PS1-AD mice had lower spontaneous alternation in the Y-maze than wild-type(WT) mice, and this was significantly reversed by AVP(4-8);(2) the prolonged escape latency of APP/PS1-AD mice in the Morris water maze was significantly decreased by AVP(4-8), and the decreased swimming time in target quadrant recovered significantly after AVP(4-8) treatment;(3) in vivo hippocampal LTP induced by high-frequency stimulation had a significant deficit in the AD mice, and this was partly rescued by AVP(4-8);(4) AVP(4-8)significantly up-regulated the expression levels of postsynaptic density 95(PSD95) and nerve growth factor(NGF)in the hippocampus of AD mice. These results reveal the beneficial effects of AVP(4-8) in APP/PS1-AD mice,showing that the intranasal administration of AVP(4-8)effectively improved the working memory and long-term spatial memory of APP/PS1-AD mice, which may be associated with the elevation of PSD95 and NGF levels in the brain and the maintenance of hippocampal synaptic plasticity.
文摘Cr-Ni-Mo-V steam-turbine rotors have been widely used as key components in power plants. In this study, a coupled thermomechano-metallurgical model was proposed to simulate the phase transformation and transformation-induced plasticity (TRIP) of a 30Cr2Ni4MoV steam-turbine rotor during a water-quenching process, which was solved using a user defined material mechanical behavior (UMAT) subroutine in ABAQUS. The thermal dilation, heat generation from plastic work, transformation latent heat, phase transformation kinetics, and TRIP were considered in the model. The thermomechanical portion of the model was used to predict the evolution of temperature, strain, and residual stress in the rotor. The phase transformation that occurred during the quenching process was considered. Constitutive models of phase transformations (austenite to pearlite, austenite to bainite, and austenite to martensite) and TRIP were developed. Experimental data were adopted and compared with the predicted results to verify the accuracy of the model. This demonstrates that the model is reliable and accurate. Then, the model was utilized to predict the temperature variation, dimensional change, minimum austenitization time, residual stress, TRIP, and volume fractions of each phase. It is concluded that this model can be a useful computational tool in the design of heat-treatment routines of steam-turbine rotors.
