microRNAs （miRNAs） play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124 （miR-124） overexpression in bone marrow-derived mesen...microRNAs （miRNAs） play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124 （miR-124） overexpression in bone marrow-derived mesenchymal stem cells. In particular, we focused on the effect of overexpression on the differentiation of bone marrow-derived mesenchymal stem cells into neurons. First, we used GeneChip technology to analyze the expression of miRNAs in bone marrow-derived mesen- chymal stem cells, neural stem cells and neurons, miR-124 expression was substantially reduced in bone marrow-derived mesenchymal stem cells compared with the other cell types. We con- structed a lentiviral vector overexpressing miR-124 and transfected it into bone marrow-derived mesenchymal stem cells. Intracellular expression levels of the neuronal early markers [3-III tu- bulin and microtubule-associated protein-2 were significantly increased, and apoptosis induced by oxygen and glucose deprivation was reduced in transfected cells. After miR-124-transfected bone marrow-derived mesenchymal stem cells were transplanted into the injured rat spinal cord, a large number of cells positive for the neuronal marker neurofilament-200 were observed in the transplanted region. The Basso-Beattie-Bresnahan locomotion scores showed that the motor function of the hind limb of rats with spinal cord injury was substantially improved. These re- sults suggest that miR-124 plays an important role in the differentiation of bone marrow-derived mesenchymal stem cells into neurons. Our findings should facilitate the development of novel strategies for enhancing the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for spinal cord injury.展开更多
Recent years have seen significant advances in the study of dissipative soliton molecules in ultrafast lasers, driven by their remarkable connections to a wide range of physical systems. However, understanding and con...Recent years have seen significant advances in the study of dissipative soliton molecules in ultrafast lasers, driven by their remarkable connections to a wide range of physical systems. However, understanding and controlling the underlying physics of soliton molecules remain elusive due to the absence of a universal physical model that adequately describes intramolecular motion. We demonstrate that resonant excitation generates breather soliton molecules, with their resonance susceptibility exhibiting high amplitude-driven operations that can be well understood within the framework of the Duffing model. Harnessing powerful experiment techniques and detailed numerical simulations, we reveal the fundamental resonant mode within intrapulse separation constrained to the 100 fs level as well as the presence of the subharmonic and overtones. Additionally, we observe chaotic dynamics arising from the multiple-frequency nonlinear interactions in a strongly dissipative regime. Our work provides a perspective on the complex interactions of dissipative optical solitons through the lens of nonlinear physics. This approach offers a simple test bed for complex nonlinear physics research, with ultrafine scanning of temporal separations of ultrashort laser pulses demonstrating significant potential for applications requiring high detection sensitivity.展开更多
We numerically and experimentally investigate the multi-pulsing mechanism in a dispersion-managed mode-locked Ybdoped fiber laser.Multi-pulsing occurs primarily owing to the inherent filtering effect of the chirped fi...We numerically and experimentally investigate the multi-pulsing mechanism in a dispersion-managed mode-locked Ybdoped fiber laser.Multi-pulsing occurs primarily owing to the inherent filtering effect of the chirped fiber Bragg grating.The spectral filtering effect restricts the spectral broadening induced by self-phase modulation and causes extra loss,leading to a decreased pump power threshold for the multi-pulsing state.Numerical simulations show that multi-pulsing emerges at a lower pump power when the spectral filter bandwidth becomes narrower.In the experiment,the spectral width increases as the net cavity dispersion approaches zero.Pulses with wider spectral widths experience more loss from the spectral filtering effect,leading to a decreased pump power threshold for multi-pulsing.Therefore,the net cavity dispersion also has an impact on the multi-pulsing threshold.Based on this conclusion,we devise a strategy to obtain single-pulsing operation with the shortest pulse width and the highest pulse energy.展开更多
Soliton molecules in optical resonators have attracted remarkable attention in nonlinear dynamics,driven by their compelling analogies with matter molecules.So far,while extensive research has been conducted on their ...Soliton molecules in optical resonators have attracted remarkable attention in nonlinear dynamics,driven by their compelling analogies with matter molecules.So far,while extensive research has been conducted on their generation,pulsations,and dissociation behaviors,the investigation of their quasi-periodic dynamics has been relatively limited.Here,we present a systematic exploration of the quasi-periodic dynamics of soliton molecules using advanced balanced optical cross-correlation techniques.The incommensurable quasi-period bifurcations constituted of cascaded Hopf bifurcations are found,providing an unambiguous pathway toward chaotic soliton molecules.The chaotic intramolecular dynamics are analyzed by time series,radio frequency spectra,phase portraits,and Lyapunov exponent analysis.In addition,we reveal an intrinsic frequency entrainment phenomenon experimentally.Such frequency entrainment provides a novel perspective on synchronization in optical resonators,encompassing the competition and interaction of oscillations across multiple temporal scales.Our experimental findings offer clear proof that the gain dynamics serve as the origin of the binding forces between solitons within the molecule,which are well supported by the numerical simulations.By advancing the understanding of sub-femtosecond resolved quasi-period dynamics of optical soliton molecules,this study contributes to the broader field of complex nonlinear dynamics,paving the way for future explorations into the intricate behaviors of solitons within optical resonators and relevant fields.展开更多
基金supported by the National Natural Science Foundation of China,No.81070971
文摘microRNAs （miRNAs） play an important regulatory role in the self-renewal and differentiation of stem cells. In this study, we examined the effects of miRNA-124 （miR-124） overexpression in bone marrow-derived mesenchymal stem cells. In particular, we focused on the effect of overexpression on the differentiation of bone marrow-derived mesenchymal stem cells into neurons. First, we used GeneChip technology to analyze the expression of miRNAs in bone marrow-derived mesen- chymal stem cells, neural stem cells and neurons, miR-124 expression was substantially reduced in bone marrow-derived mesenchymal stem cells compared with the other cell types. We con- structed a lentiviral vector overexpressing miR-124 and transfected it into bone marrow-derived mesenchymal stem cells. Intracellular expression levels of the neuronal early markers [3-III tu- bulin and microtubule-associated protein-2 were significantly increased, and apoptosis induced by oxygen and glucose deprivation was reduced in transfected cells. After miR-124-transfected bone marrow-derived mesenchymal stem cells were transplanted into the injured rat spinal cord, a large number of cells positive for the neuronal marker neurofilament-200 were observed in the transplanted region. The Basso-Beattie-Bresnahan locomotion scores showed that the motor function of the hind limb of rats with spinal cord injury was substantially improved. These re- sults suggest that miR-124 plays an important role in the differentiation of bone marrow-derived mesenchymal stem cells into neurons. Our findings should facilitate the development of novel strategies for enhancing the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for spinal cord injury.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62405128, 61827821,62220106006, and 62361136584)the China Postdoctoral Science Foundation (Grant No. 2024M751299)+2 种基金the Shenzhen Science and Technology Program (Grant Nos. SGDX202111-23114001001 and JSGGKOTD20221101115656030)the Guangdong Basic and Applied Basic Research Foundation(Grant No. 2021B1515120013)the Southern University of Science and Technology High Level of Special Funds (Grant Nos. G030230001 and G03034K004)。
文摘Recent years have seen significant advances in the study of dissipative soliton molecules in ultrafast lasers, driven by their remarkable connections to a wide range of physical systems. However, understanding and controlling the underlying physics of soliton molecules remain elusive due to the absence of a universal physical model that adequately describes intramolecular motion. We demonstrate that resonant excitation generates breather soliton molecules, with their resonance susceptibility exhibiting high amplitude-driven operations that can be well understood within the framework of the Duffing model. Harnessing powerful experiment techniques and detailed numerical simulations, we reveal the fundamental resonant mode within intrapulse separation constrained to the 100 fs level as well as the presence of the subharmonic and overtones. Additionally, we observe chaotic dynamics arising from the multiple-frequency nonlinear interactions in a strongly dissipative regime. Our work provides a perspective on the complex interactions of dissipative optical solitons through the lens of nonlinear physics. This approach offers a simple test bed for complex nonlinear physics research, with ultrafine scanning of temporal separations of ultrashort laser pulses demonstrating significant potential for applications requiring high detection sensitivity.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.U1730115,61805174,and 61827821)the Tianjin Natural Science Foundation(No.20JCQNJC01180)+1 种基金the Tianjin Research Program of Application Foundation and Advanced Technology of China(No.17JCJQJC43500)the Research and Development Program in Key Areas of Guangdong Province,China(No.2020B090922004)。
文摘We numerically and experimentally investigate the multi-pulsing mechanism in a dispersion-managed mode-locked Ybdoped fiber laser.Multi-pulsing occurs primarily owing to the inherent filtering effect of the chirped fiber Bragg grating.The spectral filtering effect restricts the spectral broadening induced by self-phase modulation and causes extra loss,leading to a decreased pump power threshold for the multi-pulsing state.Numerical simulations show that multi-pulsing emerges at a lower pump power when the spectral filter bandwidth becomes narrower.In the experiment,the spectral width increases as the net cavity dispersion approaches zero.Pulses with wider spectral widths experience more loss from the spectral filtering effect,leading to a decreased pump power threshold for multi-pulsing.Therefore,the net cavity dispersion also has an impact on the multi-pulsing threshold.Based on this conclusion,we devise a strategy to obtain single-pulsing operation with the shortest pulse width and the highest pulse energy.
基金supported by the National Natural Science Foundation of China(61975144,61827821,62220106006,and 62361136584)Shenzhen Science and Technology Program(SGDX20211123114001001 and JSGGKQTD 20221101115656030)Guangdong Basic and Applied Basic Research Foundation(2021B1515120013).
文摘Soliton molecules in optical resonators have attracted remarkable attention in nonlinear dynamics,driven by their compelling analogies with matter molecules.So far,while extensive research has been conducted on their generation,pulsations,and dissociation behaviors,the investigation of their quasi-periodic dynamics has been relatively limited.Here,we present a systematic exploration of the quasi-periodic dynamics of soliton molecules using advanced balanced optical cross-correlation techniques.The incommensurable quasi-period bifurcations constituted of cascaded Hopf bifurcations are found,providing an unambiguous pathway toward chaotic soliton molecules.The chaotic intramolecular dynamics are analyzed by time series,radio frequency spectra,phase portraits,and Lyapunov exponent analysis.In addition,we reveal an intrinsic frequency entrainment phenomenon experimentally.Such frequency entrainment provides a novel perspective on synchronization in optical resonators,encompassing the competition and interaction of oscillations across multiple temporal scales.Our experimental findings offer clear proof that the gain dynamics serve as the origin of the binding forces between solitons within the molecule,which are well supported by the numerical simulations.By advancing the understanding of sub-femtosecond resolved quasi-period dynamics of optical soliton molecules,this study contributes to the broader field of complex nonlinear dynamics,paving the way for future explorations into the intricate behaviors of solitons within optical resonators and relevant fields.
