Isotactic polybutene-1 (iPB-1) is a semi-crystalline polymer with polymorph and puzzled structural transitions. The stable form I of iPB-1 with excellent physical and mechanical properties can hardly be obtained direc...Isotactic polybutene-1 (iPB-1) is a semi-crystalline polymer with polymorph and puzzled structural transitions. The stable form I of iPB-1 with excellent physical and mechanical properties can hardly be obtained directly from the melt;instead, metastable form II will spontaneously and slowly transform into form I. Bypassing the unstable form II formation is of great significance in polymer processing, which inspires extensive research on seeking the pathways to direct formation of form I. Methods for accelerating form II to I transition are another main focus in terms of practical approach for directly obtaining form I. Taking advantage of the solvent, an ultrafast transition of iPB-1 from form II to I within minutes has been achieved at room temperature. Such an ultrafast transition is detected after treating with dichloromethane (DCM) at 30 ℃, though the framework of isothermally crystalized iPB-1 spherulite morphology could not be fully modified. The ultrafast II-I transition of iPB-1 is attributed to the solvent-induced packed-mesophase and temperature-selected chain conformation adjustment.This ultrafast transition would shed light on understanding the mechanisms of polymorphic transitions in iPB-1.展开更多
Background:Gene regulatory networks are complex dynamic systems and the reverseengineering of such networks from high-dimensional time course transcriptomic data have attracted researchers from various fields.It is al...Background:Gene regulatory networks are complex dynamic systems and the reverseengineering of such networks from high-dimensional time course transcriptomic data have attracted researchers from various fields.It is also interesting and important to study the behavior of the reconstructed networks on the basis of dynamic models and the biological mechanisms.We focus on the gene regulatory networks reconstructed using the ordinary differential equation(ODE)modelling approach and investigate the properties of these networks.Results:Controllability and stability analyses are conducted for the reconstructed gene response networks of 17 influenza infected subjects based on ODE models.Symptomatic subjects tend to have larger numbers of driver nodes,higher proportions of critical links and lower proportions of redundant links than asymptomatic subjects.We also show that the degree distribution,rather than the structure of networks,plays an important role in controlling the network in response to influenza infection.In addition,we find that the stability of high-dimensional networks is very sensitive to randomness in the reconstructed systems brought by errors in measurements and parameter estimation.Conclusions:The gene response networks of asymptomatic subjects are easier to be controlled than those of symptomatic subjects.This may indicate that the regulatory systems of asymptomatic subjects are easier to recover from disease stimulations,so these subjects are less likely to develop symptoms.Our results also suggest that stability constraint should be considered in the modelling of high-dimensional networks and the estimation of network parameters.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51673147, 51573131, and 21374077)
文摘Isotactic polybutene-1 (iPB-1) is a semi-crystalline polymer with polymorph and puzzled structural transitions. The stable form I of iPB-1 with excellent physical and mechanical properties can hardly be obtained directly from the melt;instead, metastable form II will spontaneously and slowly transform into form I. Bypassing the unstable form II formation is of great significance in polymer processing, which inspires extensive research on seeking the pathways to direct formation of form I. Methods for accelerating form II to I transition are another main focus in terms of practical approach for directly obtaining form I. Taking advantage of the solvent, an ultrafast transition of iPB-1 from form II to I within minutes has been achieved at room temperature. Such an ultrafast transition is detected after treating with dichloromethane (DCM) at 30 ℃, though the framework of isothermally crystalized iPB-1 spherulite morphology could not be fully modified. The ultrafast II-I transition of iPB-1 is attributed to the solvent-induced packed-mesophase and temperature-selected chain conformation adjustment.This ultrafast transition would shed light on understanding the mechanisms of polymorphic transitions in iPB-1.
基金This research was partially supported by the NIH grants HHSN272201000055CP30AI078498+2 种基金R01 AI087135HHSN27220201200005CHHSN266200700008C。
文摘Background:Gene regulatory networks are complex dynamic systems and the reverseengineering of such networks from high-dimensional time course transcriptomic data have attracted researchers from various fields.It is also interesting and important to study the behavior of the reconstructed networks on the basis of dynamic models and the biological mechanisms.We focus on the gene regulatory networks reconstructed using the ordinary differential equation(ODE)modelling approach and investigate the properties of these networks.Results:Controllability and stability analyses are conducted for the reconstructed gene response networks of 17 influenza infected subjects based on ODE models.Symptomatic subjects tend to have larger numbers of driver nodes,higher proportions of critical links and lower proportions of redundant links than asymptomatic subjects.We also show that the degree distribution,rather than the structure of networks,plays an important role in controlling the network in response to influenza infection.In addition,we find that the stability of high-dimensional networks is very sensitive to randomness in the reconstructed systems brought by errors in measurements and parameter estimation.Conclusions:The gene response networks of asymptomatic subjects are easier to be controlled than those of symptomatic subjects.This may indicate that the regulatory systems of asymptomatic subjects are easier to recover from disease stimulations,so these subjects are less likely to develop symptoms.Our results also suggest that stability constraint should be considered in the modelling of high-dimensional networks and the estimation of network parameters.
