Objective: To investigate the effects of carvedilol (CVD) on transmural dispersion of repolarization(TDR) and arrhythmia in pressure over-load rabbits. Methods: Left ventricular hypertrophied(LVH) rabbit model...Objective: To investigate the effects of carvedilol (CVD) on transmural dispersion of repolarization(TDR) and arrhythmia in pressure over-load rabbits. Methods: Left ventricular hypertrophied(LVH) rabbit models were established by pressure over-load; All animal models were assigned into CVD group or LVH group randomly. The action potentials of endocardium, cpicardium and transmural ECG of arterially perfused left ventricular preparations were recorded concurrently. Action potential duration (APD), TDR, ventricular arrhythmia and ultrasonic parameters, ratio of LVM to body weight (LVMI) were compared correspondingly. The stable plasma concentration of carvedilol in CVD group was detected by HPLC. APD, TDR and arrhythmia of LVH models were compared just preor post-perfusion with stable concentration of CVD. Results: In Contrast with values in LVH group, LVEFof CVD group were significantly elevated while the LVMI was remarkably reduced, TDRs were significantly shortened, and ratio of ventricular arrhythmia was lowered remarkably. No significant difference of APD, TDR and ratio of arrhythmia was found preor post-perfusion at stable plasma concentration of CVD. Conclusion: CVD can ameliorate the structure and function of pressure over-load ventricles; CVD contributes to the improvement of ventricular arrhythmia associated with its long-term effect on APD,TDR shortening ,whereas has nothing to do with its transient function on ionic channel blockade展开更多
Both the grand canonical Monte Carlo and molecular dynamics simulation methods are used to investigate the adsorption and diffusion of carbon dioxide confined in a 1.86 nm slit carbon pore at 4 temperatures from subcr...Both the grand canonical Monte Carlo and molecular dynamics simulation methods are used to investigate the adsorption and diffusion of carbon dioxide confined in a 1.86 nm slit carbon pore at 4 temperatures from subcritical (120 K) to supercritical (313 K) conditions. Layering transition, capillary condensation and adsorption hysteresis are found at 120 K. The microstructure of carbon dioxide fluid in the slit carbon pore is analyzed. The diffusion coefficients of carbon dioxide parallel to the slit wall are significantly larger than those normal to the slit wall.展开更多
A finite element model is developed to simulate the radiative transfer in 2D and 3D complex-geome-tric enclosure filled with absorbing and scattering media. This model is based on the discrete ordinates method and fin...A finite element model is developed to simulate the radiative transfer in 2D and 3D complex-geome-tric enclosure filled with absorbing and scattering media. This model is based on the discrete ordinates method and finite element theory. The finite element formulations and detailed steps of numerical calculation are given. The discrepancy of the results produced by different space and solid angle discretization is also investigated and compared. The effect of the six-node quadric element on the accuracy is analyzed by a 2D rectangular enclosure. These results indicate that the present model can simulate radiative transfer in multidimensional complex-geometric enclosure with participating media effectively and accurately.展开更多
We use Monte Carlo method to study three-state Potts model on maple leaf lattice with pure three-site interaction. The critical behavior of both ferromagnetic and antiferromagnetic cases is studied. Our results confir...We use Monte Carlo method to study three-state Potts model on maple leaf lattice with pure three-site interaction. The critical behavior of both ferromagnetic and antiferromagnetic cases is studied. Our results confirm that the critical behavior of the ferromagnetic model is independent of the lattice details and lies in the universality class of the three-state ferromagnetic Potts model. For the antiferromagnetic case the transition is of the first order. We have calculated the energy jump and critical temperature in this area. We find there is a tricritical point separating the first order and second order phases for this system.展开更多
In the present study,we aimed to probe the possibility of using mixed poloxamers as carriers to prepare ternary solid dispersion(SD)that facilitated solubility and dissolution rate of the poorly water soluble drug and...In the present study,we aimed to probe the possibility of using mixed poloxamers as carriers to prepare ternary solid dispersion(SD)that facilitated solubility and dissolution rate of the poorly water soluble drug and compare with binary SD with single poloxamer.Lidocaine(LIC)was selected as a model drug,and poloxamer 188(P188)and poloxamer 407(P407)were utilized as single and mixed carriers.Depending on DSC and the dissolution testing,the appropriate ratio of SD prepared by melting method was optimized.Ternary and binary SD was characterized by DSC,XRD,SEM and FTIR.In vitro dissolution study,phase solubility study and saturated solubility study were performed to clarify solubilization from apparent phenomena and inherent reason.Moreover,stability study under different relative humidity(RH)was investigated.Physical characterizations of binary and ternary SD exhibited the formation of eutectic mixture and the presence of molecular interaction.Compared with the pure LIC,the dissolution rate and solubility of LIC in binary and ternary SDs were enhanced.The phase solubility study revealed an AL-type curve.Furthermore,the stability test indicated that ternary and binary SD was stable.The results of this study demonstrated that SD with mixed poloxamers could improve dissolution rate and solubility of poorly water-soluble drug.展开更多
文摘Objective: To investigate the effects of carvedilol (CVD) on transmural dispersion of repolarization(TDR) and arrhythmia in pressure over-load rabbits. Methods: Left ventricular hypertrophied(LVH) rabbit models were established by pressure over-load; All animal models were assigned into CVD group or LVH group randomly. The action potentials of endocardium, cpicardium and transmural ECG of arterially perfused left ventricular preparations were recorded concurrently. Action potential duration (APD), TDR, ventricular arrhythmia and ultrasonic parameters, ratio of LVM to body weight (LVMI) were compared correspondingly. The stable plasma concentration of carvedilol in CVD group was detected by HPLC. APD, TDR and arrhythmia of LVH models were compared just preor post-perfusion with stable concentration of CVD. Results: In Contrast with values in LVH group, LVEFof CVD group were significantly elevated while the LVMI was remarkably reduced, TDRs were significantly shortened, and ratio of ventricular arrhythmia was lowered remarkably. No significant difference of APD, TDR and ratio of arrhythmia was found preor post-perfusion at stable plasma concentration of CVD. Conclusion: CVD can ameliorate the structure and function of pressure over-load ventricles; CVD contributes to the improvement of ventricular arrhythmia associated with its long-term effect on APD,TDR shortening ,whereas has nothing to do with its transient function on ionic channel blockade
基金Supported by the State Key Fundamental Research Plan of China (No. G2000048010) and National High Performance Computing Foundation of China (No. 99118).
文摘Both the grand canonical Monte Carlo and molecular dynamics simulation methods are used to investigate the adsorption and diffusion of carbon dioxide confined in a 1.86 nm slit carbon pore at 4 temperatures from subcritical (120 K) to supercritical (313 K) conditions. Layering transition, capillary condensation and adsorption hysteresis are found at 120 K. The microstructure of carbon dioxide fluid in the slit carbon pore is analyzed. The diffusion coefficients of carbon dioxide parallel to the slit wall are significantly larger than those normal to the slit wall.
基金Sponsored by the National Natural Science Foundation of China (Grant No 50576019)
文摘A finite element model is developed to simulate the radiative transfer in 2D and 3D complex-geome-tric enclosure filled with absorbing and scattering media. This model is based on the discrete ordinates method and finite element theory. The finite element formulations and detailed steps of numerical calculation are given. The discrepancy of the results produced by different space and solid angle discretization is also investigated and compared. The effect of the six-node quadric element on the accuracy is analyzed by a 2D rectangular enclosure. These results indicate that the present model can simulate radiative transfer in multidimensional complex-geometric enclosure with participating media effectively and accurately.
基金国家留学基金委资助项目,the Science Foundation for Young Teachers of Northeast Normal University of China
文摘We use Monte Carlo method to study three-state Potts model on maple leaf lattice with pure three-site interaction. The critical behavior of both ferromagnetic and antiferromagnetic cases is studied. Our results confirm that the critical behavior of the ferromagnetic model is independent of the lattice details and lies in the universality class of the three-state ferromagnetic Potts model. For the antiferromagnetic case the transition is of the first order. We have calculated the energy jump and critical temperature in this area. We find there is a tricritical point separating the first order and second order phases for this system.
基金National Natural Science Fund of China(Grant No.30801552&81274095)the third key project funded by Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization(Grant No.012092002006-10)the 55th postdoctoral project(Grant No.021062001001).
文摘In the present study,we aimed to probe the possibility of using mixed poloxamers as carriers to prepare ternary solid dispersion(SD)that facilitated solubility and dissolution rate of the poorly water soluble drug and compare with binary SD with single poloxamer.Lidocaine(LIC)was selected as a model drug,and poloxamer 188(P188)and poloxamer 407(P407)were utilized as single and mixed carriers.Depending on DSC and the dissolution testing,the appropriate ratio of SD prepared by melting method was optimized.Ternary and binary SD was characterized by DSC,XRD,SEM and FTIR.In vitro dissolution study,phase solubility study and saturated solubility study were performed to clarify solubilization from apparent phenomena and inherent reason.Moreover,stability study under different relative humidity(RH)was investigated.Physical characterizations of binary and ternary SD exhibited the formation of eutectic mixture and the presence of molecular interaction.Compared with the pure LIC,the dissolution rate and solubility of LIC in binary and ternary SDs were enhanced.The phase solubility study revealed an AL-type curve.Furthermore,the stability test indicated that ternary and binary SD was stable.The results of this study demonstrated that SD with mixed poloxamers could improve dissolution rate and solubility of poorly water-soluble drug.