The exponential stability of a class of neural networks with continuously distributed delays is investigated by employing a novel Lyapunov-Krasovskii functional. Through introducing some free-weighting matrices and th...The exponential stability of a class of neural networks with continuously distributed delays is investigated by employing a novel Lyapunov-Krasovskii functional. Through introducing some free-weighting matrices and the equivalent descriptor form, a delay-dependent stability criterion is established for the addressed systems. The condition is expressed in terms of a linear matrix inequality （LMI）, and it can be checked by resorting to the LMI in the Matlab toolbox. In addition, the proposed stability criteria do not require the monotonicity of the activation functions and the derivative of a time-varying delay being less than 1, which generalize and improve earlier methods. Finally, numerical examples are given to show the effectiveness of the obtained methods.展开更多
Significant amounts of free amino acids exist in commercially sold vegetables and fruits. Despite of the fact, only a little information is available about the free amino acid contents in foods. To utilize information...Significant amounts of free amino acids exist in commercially sold vegetables and fruits. Despite of the fact, only a little information is available about the free amino acid contents in foods. To utilize information of free amino acids in food, we have carried out the experiments to quantitate the free amino acids by derivatized with NBD-F （4-fluoro-7-nitrobenzofurazan） and analyzed on reversed-phase UHPLC （ultra-high pressure liquid chromatography） equipped with ultraviolet visible detector. Almost all of food extracts contained free amino acids including GABA （T-amino butyrate）. Contents of free amino acids vary considerably depending upon vegetables and fruits. Principal free amino acids found in vegetables and fruits were asparagine, glutamine, arginine and GABA, which are involved in important metabolic pathways in human. About 140 species of vegetables and fruits were subjected for the data base. All of the plants and fruits we examined exhibit significant amount of free amino acids, those are clearly distinct from data bases obtained after acid hydrolysis treated food samples. Since glutamate and GABA act as excitatory and inhibitory neurotransmitters in CNS, respectively; free amino acids in vegetables and fruits that we eat daily, should be an important source for the cellular metabolic activities.展开更多
基金The National Natural Science Foundation of China (No60574006)
文摘The exponential stability of a class of neural networks with continuously distributed delays is investigated by employing a novel Lyapunov-Krasovskii functional. Through introducing some free-weighting matrices and the equivalent descriptor form, a delay-dependent stability criterion is established for the addressed systems. The condition is expressed in terms of a linear matrix inequality （LMI）, and it can be checked by resorting to the LMI in the Matlab toolbox. In addition, the proposed stability criteria do not require the monotonicity of the activation functions and the derivative of a time-varying delay being less than 1, which generalize and improve earlier methods. Finally, numerical examples are given to show the effectiveness of the obtained methods.
文摘Significant amounts of free amino acids exist in commercially sold vegetables and fruits. Despite of the fact, only a little information is available about the free amino acid contents in foods. To utilize information of free amino acids in food, we have carried out the experiments to quantitate the free amino acids by derivatized with NBD-F （4-fluoro-7-nitrobenzofurazan） and analyzed on reversed-phase UHPLC （ultra-high pressure liquid chromatography） equipped with ultraviolet visible detector. Almost all of food extracts contained free amino acids including GABA （T-amino butyrate）. Contents of free amino acids vary considerably depending upon vegetables and fruits. Principal free amino acids found in vegetables and fruits were asparagine, glutamine, arginine and GABA, which are involved in important metabolic pathways in human. About 140 species of vegetables and fruits were subjected for the data base. All of the plants and fruits we examined exhibit significant amount of free amino acids, those are clearly distinct from data bases obtained after acid hydrolysis treated food samples. Since glutamate and GABA act as excitatory and inhibitory neurotransmitters in CNS, respectively; free amino acids in vegetables and fruits that we eat daily, should be an important source for the cellular metabolic activities.
