A numerical approach is an effective means of solving boundary value problems(BVPs).This study focuses on physical problems with general partial differential equations(PDEs).It investigates the solution approach throu...A numerical approach is an effective means of solving boundary value problems(BVPs).This study focuses on physical problems with general partial differential equations(PDEs).It investigates the solution approach through the standard forms of the PDE module in COMSOL.Two typical mechanics problems are exemplified:The deflection of a thin plate,which can be addressed with the dedicated finite element module,and the stress of a pure bending beamthat cannot be tackled.The procedure for the two problems regarding the three standard forms required by the PDE module is detailed.The results were in good agreement with the literature,indicating that the PDE module provides a promising means to solve complex PDEs,especially for those a dedicated finite element module has yet to be developed.展开更多
The deferred correction(DeC)is an iterative procedure,characterized by increasing the accuracy at each iteration,which can be used to design numerical methods for systems of ODEs.The main advantage of such framework i...The deferred correction(DeC)is an iterative procedure,characterized by increasing the accuracy at each iteration,which can be used to design numerical methods for systems of ODEs.The main advantage of such framework is the automatic way of getting arbitrarily high order methods,which can be put in the Runge-Kutta(RK)form.The drawback is the larger computational cost with respect to the most used RK methods.To reduce such cost,in an explicit setting,we propose an efcient modifcation:we introduce interpolation processes between the DeC iterations,decreasing the computational cost associated to the low order ones.We provide the Butcher tableaux of the new modifed methods and we study their stability,showing that in some cases the computational advantage does not afect the stability.The fexibility of the novel modifcation allows nontrivial applications to PDEs and construction of adaptive methods.The good performances of the introduced methods are broadly tested on several benchmarks both in ODE and PDE contexts.展开更多
This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering a...This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering and science.An approximate solution of the system is sought in the formof the finite series over the Müntz polynomials.By using the collocation procedure in the time interval,one gets the linear algebraic system for the coefficient of the expansion which can be easily solved numerically by a standard procedure.This technique also serves as the basis for solving the time-fractional partial differential equations(PDEs).The modified radial basis functions are used for spatial approximation of the solution.The collocation in the solution domain transforms the equation into a system of fractional ordinary differential equations similar to the one mentioned above.Several examples have verified the performance of the proposed novel technique with high accuracy and efficiency.展开更多
Summary： To further investigate the mechanisms of action of icariin （ICA）, we assessed the effects of ICA on the in vitro formation of cGMP and cAMP in isolated rabbit corpus cavernosum. Isolated segments of rabbit...Summary： To further investigate the mechanisms of action of icariin （ICA）, we assessed the effects of ICA on the in vitro formation of cGMP and cAMP in isolated rabbit corpus cavernosum. Isolated segments of rabbit corpus cavernosum were exposed to increasing concentrations of ICA and the dose-dependent accumulation of cGMP and cAMP was determined in the tissues samples by means of ^125I radioimmunoassay. Responses of the isolated tissues preparations to ICA were compared with those obtained with the reference compounds sildenafil （Sild）. Furthermore, the effects of ICA on the mRNA expression of specific cGMP-binding phosphodiesterase type Ⅴ （PDE5） in rat penis were also observed. After incubation with ICA for 6 h or 14 h respectively, the levels of PDE5 mRNA were examined by reverse transcriptase polymerase chain reaction （RT-PCR）. The results showed that ICA increased cGMP concentrations directly （P〈0.05）, but there was no significant effect on cAMP concentrations （P〉0.05）. In the presence of sodium nitroprusside （SNP）, a stimulatory agent of cGMP, both ICA and Sild increased cGMP concentrations with increasing dose （P〈0.01）. Their EC50 was 4.62 （ICA） and 0.42 （Sild） μmol/L respectively. Under the same condition, ICA and Sild unaltered cAMP level significantly （P〉0.05）. There were PDE5A 1 and PDE5A2 mRNA expressions in rat cor- pus cavernosum with PDE5A2 being the dominant isoform. ICA could obviously inhibit these two isoforms mRNA expression in rat penis, and decrease PDE5A1 more pronouncedly （P〈 0.01）. The present study indicated that the aphrodisiac mechanisms of icariin involved the NO-cGMP signal transduction pathway, with increasing cGMP levels in the corpus cavernosum smooth muscle. The inhibitory effect of icariin on PDE5 mRNA expression, especially on PDE5A1, might account for its molecular mechanisms for its long-term activity.展开更多
Phosphodiesterase （PDE） exist various forms for the different structure and property, which is one of key components of light receptors in retinal rod cells. In this paper, cloning the DNA of T-subunits Phosphodiest...Phosphodiesterase （PDE） exist various forms for the different structure and property, which is one of key components of light receptors in retinal rod cells. In this paper, cloning the DNA of T-subunits Phosphodiesterase （γ-PDE6） from cDNA library, constructing the corresponding recombinant plasmid, and purification of the protein after initial expression was studied.展开更多
A Hinf Ⅰ locus of the porcine subunit C of succinate dehydrogenase complex (SDHC) gene and a Msp Ⅰ locus of theporcine rod cGMP-phosphodiesterase γ-subunit (PDE6G) gene had been reported before, but the association...A Hinf Ⅰ locus of the porcine subunit C of succinate dehydrogenase complex (SDHC) gene and a Msp Ⅰ locus of theporcine rod cGMP-phosphodiesterase γ-subunit (PDE6G) gene had been reported before, but the association analysisbetween the different genotypes and the traits had not been done. 300 Large White × Meishan F2 pigs were used asexperimental materials to performe the PCR-RFLP analysis and association analysis for the two loci, results revealed thatthe polymorphism of the porcine subunit C of succinate dehydrogenase complex (SDHC) gene was significantly associatedwith the traits which included the carcass length, the estimated lean meat percentage, the estimated backfat thickness atlast rib, the estimated backfat thickness at last 3-4th rib, the fat meat weight, the fat meat percentage, the lean meat weight,the lean meat percentage, the ratio of lean meat to fat meat, the leaf fat weight, the backfat thickness at shoulder, thebackfat thickness at thorax-Waist, the backfat thickness at 6-7th thorax and the average daily gain. Seven other traits, themeat color value (Biceps femoris, BF), the meat marbling (Biceps femoris, BF), the water moisture (Longissimus dorsi, LD),the bone weight, the bone percentage, the loin eye width and the loin eye area, were found to be significantly correlatedwith the polymorphism of the porcine rod cGMP-phosphodiesterase γ-subunit (PDE6G) gene. Based on these results, itis necessary to apply the two genes as candidate genes to marker assistant selection (MAS) in pig breeding.展开更多
PDE is a supeffamily of enzymes that break down the important second messengers cyclic AMP （cAMP） PDE4 is the most important fami- and cyclic GMP （cGMP）. There are 11 PDE families （ PDEI-11 ） ; among them, ly i...PDE is a supeffamily of enzymes that break down the important second messengers cyclic AMP （cAMP） PDE4 is the most important fami- and cyclic GMP （cGMP）. There are 11 PDE families （ PDEI-11 ） ; among them, ly in the control of intracellular cAMP signaling. It has been established that PDE4 is an essential player in the me- diation of AD and alcoholism. Chronic alcohol consumption can cause alcohol-related dementia and 50% - 75% of detoxified alcoholics have memory or cognition impairment. The lecture will focus on the unique role of PDE4 and its isoforms （PDE4A-D） in mediating AD and alcoholism and the cellular mechanisms involved. Specifically, using mice deficient in PDE4A, PDE4B, or PDE4D, and their wild type （WT） controls, it was found that PDE4Adeficiencydecreased alcohol intake and preference and reversed Abeta42-induced memory deficits. In con- trast, deficiency of PDE4B only mimicked the ability of PDE4A-deficiency to reduce alcohol consumption, while deficiency of PDE4D only reversed Abeta42-induced memory deficits. In addition, levels of cAMP and phospho- CREB （pCREB） were increased in the hippocampus of mice deficient in PDE4A or PDE4D, which also produced reversal of Abeta42-induced decreases in pCREB. These datasuggest that PDE4 isoforms have different roles in me-diating alcohol-drinking behavior and memoryin Alzheimer＇ s disease, which are mediated by cAMP/CREB signa- ling. The results indicate PDE4A as a potential new target for alcohol-related dementia, although studies with ani- mal models of alcohol-related dementia are needed to clarify this.展开更多
基金supported by the National Natural Science Foundations of China(Grant Nos.12372073 and U20B2013)the Natural Science Basic Research Program of Shaanxi(Program No.2023-JC-QN-0030).
文摘A numerical approach is an effective means of solving boundary value problems(BVPs).This study focuses on physical problems with general partial differential equations(PDEs).It investigates the solution approach through the standard forms of the PDE module in COMSOL.Two typical mechanics problems are exemplified:The deflection of a thin plate,which can be addressed with the dedicated finite element module,and the stress of a pure bending beamthat cannot be tackled.The procedure for the two problems regarding the three standard forms required by the PDE module is detailed.The results were in good agreement with the literature,indicating that the PDE module provides a promising means to solve complex PDEs,especially for those a dedicated finite element module has yet to be developed.
文摘The deferred correction(DeC)is an iterative procedure,characterized by increasing the accuracy at each iteration,which can be used to design numerical methods for systems of ODEs.The main advantage of such framework is the automatic way of getting arbitrarily high order methods,which can be put in the Runge-Kutta(RK)form.The drawback is the larger computational cost with respect to the most used RK methods.To reduce such cost,in an explicit setting,we propose an efcient modifcation:we introduce interpolation processes between the DeC iterations,decreasing the computational cost associated to the low order ones.We provide the Butcher tableaux of the new modifed methods and we study their stability,showing that in some cases the computational advantage does not afect the stability.The fexibility of the novel modifcation allows nontrivial applications to PDEs and construction of adaptive methods.The good performances of the introduced methods are broadly tested on several benchmarks both in ODE and PDE contexts.
基金funded by the National Key Research and Development Program of China(No.2021YFB2600704)the National Natural Science Foundation of China(No.52171272)the Significant Science and Technology Project of the Ministry of Water Resources of China(No.SKS-2022112).
文摘This paper presents an efficient numerical technique for solving multi-term linear systems of fractional ordinary differential equations(FODEs)which have been widely used in modeling various phenomena in engineering and science.An approximate solution of the system is sought in the formof the finite series over the Müntz polynomials.By using the collocation procedure in the time interval,one gets the linear algebraic system for the coefficient of the expansion which can be easily solved numerically by a standard procedure.This technique also serves as the basis for solving the time-fractional partial differential equations(PDEs).The modified radial basis functions are used for spatial approximation of the solution.The collocation in the solution domain transforms the equation into a system of fractional ordinary differential equations similar to the one mentioned above.Several examples have verified the performance of the proposed novel technique with high accuracy and efficiency.
文摘Summary： To further investigate the mechanisms of action of icariin （ICA）, we assessed the effects of ICA on the in vitro formation of cGMP and cAMP in isolated rabbit corpus cavernosum. Isolated segments of rabbit corpus cavernosum were exposed to increasing concentrations of ICA and the dose-dependent accumulation of cGMP and cAMP was determined in the tissues samples by means of ^125I radioimmunoassay. Responses of the isolated tissues preparations to ICA were compared with those obtained with the reference compounds sildenafil （Sild）. Furthermore, the effects of ICA on the mRNA expression of specific cGMP-binding phosphodiesterase type Ⅴ （PDE5） in rat penis were also observed. After incubation with ICA for 6 h or 14 h respectively, the levels of PDE5 mRNA were examined by reverse transcriptase polymerase chain reaction （RT-PCR）. The results showed that ICA increased cGMP concentrations directly （P〈0.05）, but there was no significant effect on cAMP concentrations （P〉0.05）. In the presence of sodium nitroprusside （SNP）, a stimulatory agent of cGMP, both ICA and Sild increased cGMP concentrations with increasing dose （P〈0.01）. Their EC50 was 4.62 （ICA） and 0.42 （Sild） μmol/L respectively. Under the same condition, ICA and Sild unaltered cAMP level significantly （P〉0.05）. There were PDE5A 1 and PDE5A2 mRNA expressions in rat cor- pus cavernosum with PDE5A2 being the dominant isoform. ICA could obviously inhibit these two isoforms mRNA expression in rat penis, and decrease PDE5A1 more pronouncedly （P〈 0.01）. The present study indicated that the aphrodisiac mechanisms of icariin involved the NO-cGMP signal transduction pathway, with increasing cGMP levels in the corpus cavernosum smooth muscle. The inhibitory effect of icariin on PDE5 mRNA expression, especially on PDE5A1, might account for its molecular mechanisms for its long-term activity.
文摘Phosphodiesterase （PDE） exist various forms for the different structure and property, which is one of key components of light receptors in retinal rod cells. In this paper, cloning the DNA of T-subunits Phosphodiesterase （γ-PDE6） from cDNA library, constructing the corresponding recombinant plasmid, and purification of the protein after initial expression was studied.
文摘A Hinf Ⅰ locus of the porcine subunit C of succinate dehydrogenase complex (SDHC) gene and a Msp Ⅰ locus of theporcine rod cGMP-phosphodiesterase γ-subunit (PDE6G) gene had been reported before, but the association analysisbetween the different genotypes and the traits had not been done. 300 Large White × Meishan F2 pigs were used asexperimental materials to performe the PCR-RFLP analysis and association analysis for the two loci, results revealed thatthe polymorphism of the porcine subunit C of succinate dehydrogenase complex (SDHC) gene was significantly associatedwith the traits which included the carcass length, the estimated lean meat percentage, the estimated backfat thickness atlast rib, the estimated backfat thickness at last 3-4th rib, the fat meat weight, the fat meat percentage, the lean meat weight,the lean meat percentage, the ratio of lean meat to fat meat, the leaf fat weight, the backfat thickness at shoulder, thebackfat thickness at thorax-Waist, the backfat thickness at 6-7th thorax and the average daily gain. Seven other traits, themeat color value (Biceps femoris, BF), the meat marbling (Biceps femoris, BF), the water moisture (Longissimus dorsi, LD),the bone weight, the bone percentage, the loin eye width and the loin eye area, were found to be significantly correlatedwith the polymorphism of the porcine rod cGMP-phosphodiesterase γ-subunit (PDE6G) gene. Based on these results, itis necessary to apply the two genes as candidate genes to marker assistant selection (MAS) in pig breeding.
文摘PDE is a supeffamily of enzymes that break down the important second messengers cyclic AMP （cAMP） PDE4 is the most important fami- and cyclic GMP （cGMP）. There are 11 PDE families （ PDEI-11 ） ; among them, ly in the control of intracellular cAMP signaling. It has been established that PDE4 is an essential player in the me- diation of AD and alcoholism. Chronic alcohol consumption can cause alcohol-related dementia and 50% - 75% of detoxified alcoholics have memory or cognition impairment. The lecture will focus on the unique role of PDE4 and its isoforms （PDE4A-D） in mediating AD and alcoholism and the cellular mechanisms involved. Specifically, using mice deficient in PDE4A, PDE4B, or PDE4D, and their wild type （WT） controls, it was found that PDE4Adeficiencydecreased alcohol intake and preference and reversed Abeta42-induced memory deficits. In con- trast, deficiency of PDE4B only mimicked the ability of PDE4A-deficiency to reduce alcohol consumption, while deficiency of PDE4D only reversed Abeta42-induced memory deficits. In addition, levels of cAMP and phospho- CREB （pCREB） were increased in the hippocampus of mice deficient in PDE4A or PDE4D, which also produced reversal of Abeta42-induced decreases in pCREB. These datasuggest that PDE4 isoforms have different roles in me-diating alcohol-drinking behavior and memoryin Alzheimer＇ s disease, which are mediated by cAMP/CREB signa- ling. The results indicate PDE4A as a potential new target for alcohol-related dementia, although studies with ani- mal models of alcohol-related dementia are needed to clarify this.
