The effects of random long-range connections （shortcuts） on the transitions of neural firing patterns in coupled Hindmarsh-Rose neurons are investigated, where each neuron is subjected to an external current. It is ...The effects of random long-range connections （shortcuts） on the transitions of neural firing patterns in coupled Hindmarsh-Rose neurons are investigated, where each neuron is subjected to an external current. It is found that, on one hand, the system can achieve the transition of neural firing patterns from the fewer-period state to the multi-period one, when the number of the added shortcuts in the neural network is greater than a threshold value, indicating the occurrence of in-transition of neural firing patterns. On the other hand, for a stronger coupling strength, we can also find the similar but reverse results by adding some proper random connections. In addition, the influences of system size and coupling strength on such transition behavior, as well as the internality between the transition degree of firing patterns and its critical characteristics for different external stimulation current, are also discussed.展开更多
目的:研究糖尿病小鼠胰腺组织中Netrin-1的表达并探讨其在糖尿病发生过程中的作用。方法:C57BL/6J小鼠随机分为正常对照组和糖尿病模型组,应用RT-PCR和Western blot方法分别检测小鼠胰腺组织中Netrin-1 m RNA和蛋白的变化;在正常和异常...目的:研究糖尿病小鼠胰腺组织中Netrin-1的表达并探讨其在糖尿病发生过程中的作用。方法:C57BL/6J小鼠随机分为正常对照组和糖尿病模型组,应用RT-PCR和Western blot方法分别检测小鼠胰腺组织中Netrin-1 m RNA和蛋白的变化;在正常和异常葡萄糖浓度下培养大鼠胰岛细胞瘤细胞(ins-1),MTT检测细胞活性,RT-PCR和Western blot方法分别测定Netrin-1m RNA和蛋白的表达情况。结果:糖尿病小鼠胰腺组织内Netrin-1的m RNA和蛋白表达增加,高浓度葡萄糖刺激ins-1细胞上调Netrin-1 m RNA和蛋白的表达。结论:糖尿病小鼠胰腺组织表达Netrin-1的水平增加,这与血糖异常相关,Netrin-1可能与糖尿病的发生发展相关。展开更多
BACKGROUND： Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 （NT-3）contributes to regeneration of nerve f...BACKGROUND： Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 （NT-3）contributes to regeneration of nerve fibers in the spinal cord and motor function recovery. The combination of Nogo-neutralizing antibody IN-1 and NT-3 is hypothesized to produce better outcomes and facilitate axonal regeneration by affecting c-Fos and c-Jun protein expression. OBJECTIVE： To investigate the combined effects of Nogo-neutralizing antibody IN-1 and NT-3 on c-Fos and c-Jun protein levels in the injured spinal cord. DESIGN, TIME AND SETTING： A randomized, controlled study was performed at the Laboratory of Neuroanatomy, Xiangya Medical College, Central South University and the Central Laboratory of Third Xiangya Hospital of China from June 2005 to December 2007. MATERIALS： NT-3 （Peprotech, USA） and Nogo-neutralizing antibody IN-1 （Santa Cruz Biotechnology, USA） were used in this study. METHODS： Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of rat spinal cord, which is equivalent to the T8 level in the human spine. A total of 120 rats were equally and randomly assigned to three groups： model （0.2 μL saline）, IN-1 （0.2 μL IN-1）, and IN-1/NT-3 （0.2 μL IN-1 ＋ 0.2 μL NT-3）. The compounds were separately infused into transection sites on the side of head. MAIN OUTCOME MEASURES： Western blot analysis was employed to measure c-Fos and c-Jun protein expression in the injured spinal cord at 15, 30 minutes, 1,2, 4, 6, 8, and 12 hours following surgery. RESULTS： Following spinal cord injury, c-Fos and c-Jun protein expression were increased and peaked at 4 6 hours. Following injection of IN-1 or the combination of IN-1 and NT-3, c-Fos protein expression was significantly reduced in the injured spinal cord （P 〈 0.05 or P 〈 0.01） （with the exception of the 15 minute time point）. However, c-Jun protein expression was significantly increased （P〈 0.05 or P〈 0.01） （with the exception of the 15 and 30 minute time points）. Combined application of IN-1 and NT-3 resulted in significantly altered protein expression compared to IN-1 alone. CONCLUSION： IN-1 increases c-Jun protein levels and protects the injured spinal cord by inhibiting c-Fos protein levels. Moreover, the effects of IN-1 combined with NT-3 are more significant than with IN-1 alone.展开更多
A spinal cord hemisection injury model was established in rats. Treatment with IN-1 and/or neurotrophin-3 was found to regulate the expression of growth-associated protein 43, nerve growth factor, and basic fibroblast...A spinal cord hemisection injury model was established in rats. Treatment with IN-1 and/or neurotrophin-3 was found to regulate the expression of growth-associated protein 43, nerve growth factor, and basic fibroblast growth factor genes in the injured spinal cord tissues; transcript levels were first increased and then decreased. Expression levels reached a peak at days 7 （growth-associated protein 43） or 14 （nerve growth factor and basic fibroblast growth factor） following spinal cord injury. Combined treatment with neurotrophin-3 and IN-1 achieved the most apparent effect on the expression and recovery of motor function. These findings confirm that combined therapy with neurotrophin-3 and IN-1 can increase expression of growth factors in the injured spinal cord tissues and promote the axonal reaeneration.展开更多
Previous studies show that transient axonal glycoprotein-1, a ligand of amyloid precursor pro- tein, increases the secretion of amyloid precursor protein intracellular domain and is involved in apoptosis in Alzheimer...Previous studies show that transient axonal glycoprotein-1, a ligand of amyloid precursor pro- tein, increases the secretion of amyloid precursor protein intracellular domain and is involved in apoptosis in Alzheimer＇s disease. In this study, we examined the effects of transient axonal glyco- protein-1 on U251 glioma cells. 3-（4,5-Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay showed that transient axonal glycoprotein-1 did not inhibit the proliferation of U251 cells, but promoted cell viability. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that transient axonal glycoprotein-1 did not induce U251 cell apoptosis. Real-time PCR revealed that transient axonal glycoprotein-1 substantially upregulated levels of amyloid precursor protein intracellular C-terminal domain, and p53 and epidermal growth factor recep- tor mRNA expression. Thus, transient axonal glycoprotein-1 increased apoptosis-related gene expression in U251 cells without inducing apoptosis. Instead, transient axonal glycoprotein-1 promoted the proliferation of these glioma cells.展开更多
In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AMS 4777 as the fille...In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AMS 4777 as the filler metal. The influence of gap size and bonding time on the joints was investigated. For example, complete isothermal solidification time for 40μm gap size was obtained as 45 min. In the case of lack of completion of isothermal solidification step, the remained molten interlayer cooled in the bonding zone under non-equilibrium condition andγ–γ′ eutectic phase formed in that area. The relationship between gap size and holding time was not linear. With the increase in gap size, eutectic phase width became thicker. In the diffusion affected zone, a much larger amount of alloying elements were observed reaching a peak. These peaks might be due to the formation of boride or silicide intermetallic. With the increase in gap size, the time required for bonding will increase, so the alloying elements have more time for diffusion and distribution in farther areas. As a result, concentrations of alloying elements decreased slightly with the increase in the gap size. The present bi-phasic model did not properly predict the complete isothermal solidification time for IN-738LC-AMS 4777-IN-738LC TLP bonding system.展开更多
Influences of gap size and cyclic-thermal-shock treatment on the mechanical properties of transient liquid phase（TLP） bonded IN-738 LC superalloy were investigated. For this purpose, TLP bonding of IN-738 LC superal...Influences of gap size and cyclic-thermal-shock treatment on the mechanical properties of transient liquid phase（TLP） bonded IN-738 LC superalloy were investigated. For this purpose, TLP bonding of IN-738 LC superalloy was carried out in a vacuum furnace using powdered AMS 4777 as the filler metal. The results showed that isothermal solidified zone（ISZ） consisted of Ni solid-solution and the distribution of alloying elements was homogeneous. High hardness of HV 409 and high shear strength of 506 MPa were observed in 40 μm gap sample. Alloying elements formed γ′ precipitates and the solid-solution in the ISZ. Hardness and shear strength of bonds were reduced with increasing the gap size（in range of 40-120 μm）. The fractured surfaces of complete isothermal solidified bonds showed dimpled rupture, but athermal solidified bonds showed cleavage fracture surface. 10, 20, 30 and 40 thermal-shock cycles were applied to 80 μm gap samples, respectively. The shear strength of the bond was measured to be 268 MPa after the 40 th thermal-shock cycle. The sample with gap size of 80 μm was failed due to crack nucleation on faying surface at 45 th thermal-shock cycle. The amount of the produced brittleness due to quenching the samples in water bath was attributed to the number of thermal-shock cycles.展开更多
文摘The effects of random long-range connections （shortcuts） on the transitions of neural firing patterns in coupled Hindmarsh-Rose neurons are investigated, where each neuron is subjected to an external current. It is found that, on one hand, the system can achieve the transition of neural firing patterns from the fewer-period state to the multi-period one, when the number of the added shortcuts in the neural network is greater than a threshold value, indicating the occurrence of in-transition of neural firing patterns. On the other hand, for a stronger coupling strength, we can also find the similar but reverse results by adding some proper random connections. In addition, the influences of system size and coupling strength on such transition behavior, as well as the internality between the transition degree of firing patterns and its critical characteristics for different external stimulation current, are also discussed.
文摘目的:研究糖尿病小鼠胰腺组织中Netrin-1的表达并探讨其在糖尿病发生过程中的作用。方法:C57BL/6J小鼠随机分为正常对照组和糖尿病模型组,应用RT-PCR和Western blot方法分别检测小鼠胰腺组织中Netrin-1 m RNA和蛋白的变化;在正常和异常葡萄糖浓度下培养大鼠胰岛细胞瘤细胞(ins-1),MTT检测细胞活性,RT-PCR和Western blot方法分别测定Netrin-1m RNA和蛋白的表达情况。结果:糖尿病小鼠胰腺组织内Netrin-1的m RNA和蛋白表达增加,高浓度葡萄糖刺激ins-1细胞上调Netrin-1 m RNA和蛋白的表达。结论:糖尿病小鼠胰腺组织表达Netrin-1的水平增加,这与血糖异常相关,Netrin-1可能与糖尿病的发生发展相关。
基金a Grant from Department of Health of Hunan Province of China,No.B2005-076
文摘BACKGROUND： Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 （NT-3）contributes to regeneration of nerve fibers in the spinal cord and motor function recovery. The combination of Nogo-neutralizing antibody IN-1 and NT-3 is hypothesized to produce better outcomes and facilitate axonal regeneration by affecting c-Fos and c-Jun protein expression. OBJECTIVE： To investigate the combined effects of Nogo-neutralizing antibody IN-1 and NT-3 on c-Fos and c-Jun protein levels in the injured spinal cord. DESIGN, TIME AND SETTING： A randomized, controlled study was performed at the Laboratory of Neuroanatomy, Xiangya Medical College, Central South University and the Central Laboratory of Third Xiangya Hospital of China from June 2005 to December 2007. MATERIALS： NT-3 （Peprotech, USA） and Nogo-neutralizing antibody IN-1 （Santa Cruz Biotechnology, USA） were used in this study. METHODS： Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of rat spinal cord, which is equivalent to the T8 level in the human spine. A total of 120 rats were equally and randomly assigned to three groups： model （0.2 μL saline）, IN-1 （0.2 μL IN-1）, and IN-1/NT-3 （0.2 μL IN-1 ＋ 0.2 μL NT-3）. The compounds were separately infused into transection sites on the side of head. MAIN OUTCOME MEASURES： Western blot analysis was employed to measure c-Fos and c-Jun protein expression in the injured spinal cord at 15, 30 minutes, 1,2, 4, 6, 8, and 12 hours following surgery. RESULTS： Following spinal cord injury, c-Fos and c-Jun protein expression were increased and peaked at 4 6 hours. Following injection of IN-1 or the combination of IN-1 and NT-3, c-Fos protein expression was significantly reduced in the injured spinal cord （P 〈 0.05 or P 〈 0.01） （with the exception of the 15 minute time point）. However, c-Jun protein expression was significantly increased （P〈 0.05 or P〈 0.01） （with the exception of the 15 and 30 minute time points）. Combined application of IN-1 and NT-3 resulted in significantly altered protein expression compared to IN-1 alone. CONCLUSION： IN-1 increases c-Jun protein levels and protects the injured spinal cord by inhibiting c-Fos protein levels. Moreover, the effects of IN-1 combined with NT-3 are more significant than with IN-1 alone.
基金a project by Hunan Provincial Health Department, No. B2005-076
文摘A spinal cord hemisection injury model was established in rats. Treatment with IN-1 and/or neurotrophin-3 was found to regulate the expression of growth-associated protein 43, nerve growth factor, and basic fibroblast growth factor genes in the injured spinal cord tissues; transcript levels were first increased and then decreased. Expression levels reached a peak at days 7 （growth-associated protein 43） or 14 （nerve growth factor and basic fibroblast growth factor） following spinal cord injury. Combined treatment with neurotrophin-3 and IN-1 achieved the most apparent effect on the expression and recovery of motor function. These findings confirm that combined therapy with neurotrophin-3 and IN-1 can increase expression of growth factors in the injured spinal cord tissues and promote the axonal reaeneration.
基金supported by grants from the National Natural Science Foundation of China,No.81171179,81272439the Key Sci-Tech Research Projects of Guangdong Province in China,No.2008A030201019the Guangzhou Municipal Science and Technology Project in China,No.09B52120112-2009J1-C418-2,No.2008A1-E4011-6
文摘Previous studies show that transient axonal glycoprotein-1, a ligand of amyloid precursor pro- tein, increases the secretion of amyloid precursor protein intracellular domain and is involved in apoptosis in Alzheimer＇s disease. In this study, we examined the effects of transient axonal glyco- protein-1 on U251 glioma cells. 3-（4,5-Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay showed that transient axonal glycoprotein-1 did not inhibit the proliferation of U251 cells, but promoted cell viability. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed that transient axonal glycoprotein-1 did not induce U251 cell apoptosis. Real-time PCR revealed that transient axonal glycoprotein-1 substantially upregulated levels of amyloid precursor protein intracellular C-terminal domain, and p53 and epidermal growth factor recep- tor mRNA expression. Thus, transient axonal glycoprotein-1 increased apoptosis-related gene expression in U251 cells without inducing apoptosis. Instead, transient axonal glycoprotein-1 promoted the proliferation of these glioma cells.
文摘In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AMS 4777 as the filler metal. The influence of gap size and bonding time on the joints was investigated. For example, complete isothermal solidification time for 40μm gap size was obtained as 45 min. In the case of lack of completion of isothermal solidification step, the remained molten interlayer cooled in the bonding zone under non-equilibrium condition andγ–γ′ eutectic phase formed in that area. The relationship between gap size and holding time was not linear. With the increase in gap size, eutectic phase width became thicker. In the diffusion affected zone, a much larger amount of alloying elements were observed reaching a peak. These peaks might be due to the formation of boride or silicide intermetallic. With the increase in gap size, the time required for bonding will increase, so the alloying elements have more time for diffusion and distribution in farther areas. As a result, concentrations of alloying elements decreased slightly with the increase in the gap size. The present bi-phasic model did not properly predict the complete isothermal solidification time for IN-738LC-AMS 4777-IN-738LC TLP bonding system.
文摘Influences of gap size and cyclic-thermal-shock treatment on the mechanical properties of transient liquid phase（TLP） bonded IN-738 LC superalloy were investigated. For this purpose, TLP bonding of IN-738 LC superalloy was carried out in a vacuum furnace using powdered AMS 4777 as the filler metal. The results showed that isothermal solidified zone（ISZ） consisted of Ni solid-solution and the distribution of alloying elements was homogeneous. High hardness of HV 409 and high shear strength of 506 MPa were observed in 40 μm gap sample. Alloying elements formed γ′ precipitates and the solid-solution in the ISZ. Hardness and shear strength of bonds were reduced with increasing the gap size（in range of 40-120 μm）. The fractured surfaces of complete isothermal solidified bonds showed dimpled rupture, but athermal solidified bonds showed cleavage fracture surface. 10, 20, 30 and 40 thermal-shock cycles were applied to 80 μm gap samples, respectively. The shear strength of the bond was measured to be 268 MPa after the 40 th thermal-shock cycle. The sample with gap size of 80 μm was failed due to crack nucleation on faying surface at 45 th thermal-shock cycle. The amount of the produced brittleness due to quenching the samples in water bath was attributed to the number of thermal-shock cycles.
