The Galerkin and least-squares methods are two classes of the most popular Krylov subspace methOds for solving large linear systems of equations. Unfortunately, both the methods may suffer from serious breakdowns of t...The Galerkin and least-squares methods are two classes of the most popular Krylov subspace methOds for solving large linear systems of equations. Unfortunately, both the methods may suffer from serious breakdowns of the same type: In a breakdown situation the Galerkin method is unable to calculate an approximate solution, while the least-squares method, although does not really break down, is unsucessful in reducing the norm of its residual. In this paper we first establish a unified theorem which gives a relationship between breakdowns in the two methods. We further illustrate theoretically and experimentally that if the coefficient matrix of a lienar system is of high defectiveness with the associated eigenvalues less than 1, then the restarted Galerkin and least-squares methods will be in great risks of complete breakdowns. It appears that our findings may help to understand phenomena observed practically and to derive treatments for breakdowns of this type.展开更多
Summary: The effect of the autonomic nerves on the transmural dispersion of ventricular repolarization (TDR) under acute myocardial ischemia in intact canine was investigated. Using the monophasic action potential (MA...Summary: The effect of the autonomic nerves on the transmural dispersion of ventricular repolarization (TDR) under acute myocardial ischemia in intact canine was investigated. Using the monophasic action potential (MAP) recording technique, MAPs of the epicardium (Epi), midmyocardium (Mid) and endocardium (Endo) were recorded simultaneously by specially designed plunge-needle electrodes at the left ventricular free wall under acute myocardial ischemia in 12 open-chest dogs. MAPD 90 and TDR among three myocardial layers as well as the incidence of the early afterdepolarization (EAD) before autonomic nervous stimulation and during autonomic nervous stimulation were compared. It was found that 10 min after acute myocardial ischemia, TDR was increased from 55±8 ms to 86±15 ms during sympathetic stimulation (P<0.01). The TDR (53±9 ms) during parasympathetic stimulation was not significantly different from that of the control (55±8 ms) (P>0.05). The EAD was elicited in the Mid of 2 dogs (16 %) 10 min after acute myocardial ischemia, but the EAD were elicited in the Mid of 7 dogs (58 %) during sympathetic stimulation (P<0.01). It was concluded that: (1) Sympathetic stimulation can increase the transmural dispersion of repolari-zation and induce early afterdepolarizations in the Mid under acute myocardial ischemia, which provide the opportunity for the ventricular arrhythmia developing; (2) Parasympathetic stimulation has no significant effect on the transmural dispersion of repolarization under myocardial ischemia.展开更多
Sampled-data iterative learning control (SILC) for singular systems is addressed for the first time. With the introduction of the constrained relative degree, an SILC algorithm combined with a feedback control law is ...Sampled-data iterative learning control (SILC) for singular systems is addressed for the first time. With the introduction of the constrained relative degree, an SILC algorithm combined with a feedback control law is proposed for singular systems. Convergence of the algorithm is proved in sup-norm, while the conventional convergence analysis is in λ-norm. The final tracking error uniformly converges to a small residual set whose level of magnitude depends on the system dynamics and the sampling-period. Due to inequalities to estimate the level of the existing results of SILC, convergence is guaranteed not only at the sampling instants but on the entire operation interval, so that the inter-sample behavior is guaranteed, which is more practical for real implementation.展开更多
Two new ionone derivatives, named rhododendrone and rhododendronside, were isolated from the alcoholic extract of the aerial parts of Rhododendron przwalskii Maxim. Their structures were elucidated on the basis of spe...Two new ionone derivatives, named rhododendrone and rhododendronside, were isolated from the alcoholic extract of the aerial parts of Rhododendron przwalskii Maxim. Their structures were elucidated on the basis of spectroscopic analysis展开更多
The time-domain BEM was developed to analyze the dynamic stress intensity factor ( DSIF) of 3-D elastodynamic crack problems. To simulate the stress singularity along the front of a crack, eight-node isoparametric sin...The time-domain BEM was developed to analyze the dynamic stress intensity factor ( DSIF) of 3-D elastodynamic crack problems. To simulate the stress singularity along the front of a crack, eight-node isoparametric singular elements were used, and the DSIF for a semi-circular surface crack was firstly calculated based on displacement equation using the time-domain BEM formulation. The new scheme to determine the time step was brought forward. By the dynamic analysis program of time-domain BEM compiled by its, several numerical examples are presented, which demonstrate the unconditional stability and high accuracy of time-domain BEM applied to 3-D elastodynamic crack problems.展开更多
Objective: To compare the expression of Epstein-Barr virus encoded LMP1 and E-cadherin/β-catenin in primary and metastatic nasopharyngeal carcinoma (NPC) for the purpose of understanding their relationship. Methods: ...Objective: To compare the expression of Epstein-Barr virus encoded LMP1 and E-cadherin/β-catenin in primary and metastatic nasopharyngeal carcinoma (NPC) for the purpose of understanding their relationship. Methods: Twenty-two pairs of biopsies taken from the nasopharynx and cervical lymph node(s) of the same patient with nasopharyngeal carcinoma were collected. The expression of LMP1, E-cadherin and β-catenin was observed on immunostained slides using LSAB method. Results: The expression rate of LMP1 in the 22 metastatic tumors (86.36%, 19/22) was significantly higher than that in the 22 primary growths (68.18%, 15/22), P<0.05. The mean expression percentages of E-cadherin and β-catenin in metastatic tumors (50.11%±22.53% and 66.36±21.05%, respectively) were significantly lower than those in primary growths (71.52±24.34 % and 79.40%±15.05%, respectively), P<0.05. There was a positive correlation between the expressions of E-cadherin and β-catenin either in primary growths or metastatic tumors. Conclusion: The LMP1 is more likely to be expressed in metastatic neoplastic cells of NPC than in primary carcinoma cells, and on the contrary the expression of E-cadherin/β-catenin in metastatic cells was decreased. Accordingly, the LMP1 might have the ability to downregulate the expression of E-cadherin/β-catenin, resulting in enhancement of the invasive capacity of metastatic NPC cells.展开更多
文摘The Galerkin and least-squares methods are two classes of the most popular Krylov subspace methOds for solving large linear systems of equations. Unfortunately, both the methods may suffer from serious breakdowns of the same type: In a breakdown situation the Galerkin method is unable to calculate an approximate solution, while the least-squares method, although does not really break down, is unsucessful in reducing the norm of its residual. In this paper we first establish a unified theorem which gives a relationship between breakdowns in the two methods. We further illustrate theoretically and experimentally that if the coefficient matrix of a lienar system is of high defectiveness with the associated eigenvalues less than 1, then the restarted Galerkin and least-squares methods will be in great risks of complete breakdowns. It appears that our findings may help to understand phenomena observed practically and to derive treatments for breakdowns of this type.
文摘Summary: The effect of the autonomic nerves on the transmural dispersion of ventricular repolarization (TDR) under acute myocardial ischemia in intact canine was investigated. Using the monophasic action potential (MAP) recording technique, MAPs of the epicardium (Epi), midmyocardium (Mid) and endocardium (Endo) were recorded simultaneously by specially designed plunge-needle electrodes at the left ventricular free wall under acute myocardial ischemia in 12 open-chest dogs. MAPD 90 and TDR among three myocardial layers as well as the incidence of the early afterdepolarization (EAD) before autonomic nervous stimulation and during autonomic nervous stimulation were compared. It was found that 10 min after acute myocardial ischemia, TDR was increased from 55±8 ms to 86±15 ms during sympathetic stimulation (P<0.01). The TDR (53±9 ms) during parasympathetic stimulation was not significantly different from that of the control (55±8 ms) (P>0.05). The EAD was elicited in the Mid of 2 dogs (16 %) 10 min after acute myocardial ischemia, but the EAD were elicited in the Mid of 7 dogs (58 %) during sympathetic stimulation (P<0.01). It was concluded that: (1) Sympathetic stimulation can increase the transmural dispersion of repolari-zation and induce early afterdepolarizations in the Mid under acute myocardial ischemia, which provide the opportunity for the ventricular arrhythmia developing; (2) Parasympathetic stimulation has no significant effect on the transmural dispersion of repolarization under myocardial ischemia.
文摘Sampled-data iterative learning control (SILC) for singular systems is addressed for the first time. With the introduction of the constrained relative degree, an SILC algorithm combined with a feedback control law is proposed for singular systems. Convergence of the algorithm is proved in sup-norm, while the conventional convergence analysis is in λ-norm. The final tracking error uniformly converges to a small residual set whose level of magnitude depends on the system dynamics and the sampling-period. Due to inequalities to estimate the level of the existing results of SILC, convergence is guaranteed not only at the sampling instants but on the entire operation interval, so that the inter-sample behavior is guaranteed, which is more practical for real implementation.
文摘Two new ionone derivatives, named rhododendrone and rhododendronside, were isolated from the alcoholic extract of the aerial parts of Rhododendron przwalskii Maxim. Their structures were elucidated on the basis of spectroscopic analysis
文摘The time-domain BEM was developed to analyze the dynamic stress intensity factor ( DSIF) of 3-D elastodynamic crack problems. To simulate the stress singularity along the front of a crack, eight-node isoparametric singular elements were used, and the DSIF for a semi-circular surface crack was firstly calculated based on displacement equation using the time-domain BEM formulation. The new scheme to determine the time step was brought forward. By the dynamic analysis program of time-domain BEM compiled by its, several numerical examples are presented, which demonstrate the unconditional stability and high accuracy of time-domain BEM applied to 3-D elastodynamic crack problems.
基金This work was supported by the National Natural Science Foundation of China (No. 39730200-II).
文摘Objective: To compare the expression of Epstein-Barr virus encoded LMP1 and E-cadherin/β-catenin in primary and metastatic nasopharyngeal carcinoma (NPC) for the purpose of understanding their relationship. Methods: Twenty-two pairs of biopsies taken from the nasopharynx and cervical lymph node(s) of the same patient with nasopharyngeal carcinoma were collected. The expression of LMP1, E-cadherin and β-catenin was observed on immunostained slides using LSAB method. Results: The expression rate of LMP1 in the 22 metastatic tumors (86.36%, 19/22) was significantly higher than that in the 22 primary growths (68.18%, 15/22), P<0.05. The mean expression percentages of E-cadherin and β-catenin in metastatic tumors (50.11%±22.53% and 66.36±21.05%, respectively) were significantly lower than those in primary growths (71.52±24.34 % and 79.40%±15.05%, respectively), P<0.05. There was a positive correlation between the expressions of E-cadherin and β-catenin either in primary growths or metastatic tumors. Conclusion: The LMP1 is more likely to be expressed in metastatic neoplastic cells of NPC than in primary carcinoma cells, and on the contrary the expression of E-cadherin/β-catenin in metastatic cells was decreased. Accordingly, the LMP1 might have the ability to downregulate the expression of E-cadherin/β-catenin, resulting in enhancement of the invasive capacity of metastatic NPC cells.
