The dynamics of plasma and shockwave expansion during two femtosecond laser pulse ablation of fused silica are studied using a time-resolved shadowgraph imaging technique. The experimental results reveal that during t...The dynamics of plasma and shockwave expansion during two femtosecond laser pulse ablation of fused silica are studied using a time-resolved shadowgraph imaging technique. The experimental results reveal that during the second pulse irradiation on the crater induced by the first pulse, the expansion of the plasma and shockwave is enhanced in the longitudinal direction. The plasma model and Fresnel diffraction theory are combined to calculate the laser intensity distribution by considering the change in surface morphology and transient material properties. The theoretical results show that after the free electron density induced by the rising edge of the pulse reaches the critical density, the originally transparent surface is transformed into a transient high-reflectivity surface(metallic state). Thus, the crater with a concave-lens-like morphology can tremendously reflect and refocus the latter part of the laser pulse, leading to a strong laser field with an intensity even higher than the incident intensity. This strong refocused laser pulse results in a stronger laser-induced air breakdown and enhances the subsequent expansion of the plasma and shockwave. In addition, similar shadowgraphs are also recorded in the single-pulse ablation of a concave microlens, providing experimental evidence for the enhancement mechanism.展开更多
Focal adhesion complexes function as the mediators of cell-extracellular matrix interactions to sense and transmit the extracellular signals.Previous studies have demonstrated that cardiomyocyte focal adhesions can be...Focal adhesion complexes function as the mediators of cell-extracellular matrix interactions to sense and transmit the extracellular signals.Previous studies have demonstrated that cardiomyocyte focal adhesions can be modulated by surface topographic features.However,the response of focal adhesions to dynamic surface topographic changes remains underexplored.To study this dynamic responsiveness of focal adhesions,we utilized a shape memory polymer-based substrate that can produce a flat-to-wrinkle surface transition triggered by an increase of temperature.Using this dynamic culture system,we analyzed three proteins(paxillin,vinculin and zyxin)from different layers of the focal adhesion complex in response to dynamic extracellular topographic change.Hence,we quantified the dynamic profile of cardiomyocyte focal adhesion in a time-dependent manner,which provides new understanding of dynamic cardiac mechanobiology.展开更多
基金National Natural Science Foundation of China(NSFC)(51605029,91323301)
文摘The dynamics of plasma and shockwave expansion during two femtosecond laser pulse ablation of fused silica are studied using a time-resolved shadowgraph imaging technique. The experimental results reveal that during the second pulse irradiation on the crater induced by the first pulse, the expansion of the plasma and shockwave is enhanced in the longitudinal direction. The plasma model and Fresnel diffraction theory are combined to calculate the laser intensity distribution by considering the change in surface morphology and transient material properties. The theoretical results show that after the free electron density induced by the rising edge of the pulse reaches the critical density, the originally transparent surface is transformed into a transient high-reflectivity surface(metallic state). Thus, the crater with a concave-lens-like morphology can tremendously reflect and refocus the latter part of the laser pulse, leading to a strong laser field with an intensity even higher than the incident intensity. This strong refocused laser pulse results in a stronger laser-induced air breakdown and enhances the subsequent expansion of the plasma and shockwave. In addition, similar shadowgraphs are also recorded in the single-pulse ablation of a concave microlens, providing experimental evidence for the enhancement mechanism.
基金supported by the NIH NICHD[R01HD101130]NSF[CBET-1804875,CBET-1943798 and CMMI-2130192]+3 种基金NSF[DMR-1609523 and CMMI-2022421]Syracuse University intramural CUSE GrantGerber GrantBioInspired Institute Seed Grant.
文摘Focal adhesion complexes function as the mediators of cell-extracellular matrix interactions to sense and transmit the extracellular signals.Previous studies have demonstrated that cardiomyocyte focal adhesions can be modulated by surface topographic features.However,the response of focal adhesions to dynamic surface topographic changes remains underexplored.To study this dynamic responsiveness of focal adhesions,we utilized a shape memory polymer-based substrate that can produce a flat-to-wrinkle surface transition triggered by an increase of temperature.Using this dynamic culture system,we analyzed three proteins(paxillin,vinculin and zyxin)from different layers of the focal adhesion complex in response to dynamic extracellular topographic change.Hence,we quantified the dynamic profile of cardiomyocyte focal adhesion in a time-dependent manner,which provides new understanding of dynamic cardiac mechanobiology.
