Ischemic accumulation of succinate causes cerebral damage by excess production of reactive oxygen species. However, it is unknown whether ischemic accumulation of succinate affects neural stem cell proliferation. In t...Ischemic accumulation of succinate causes cerebral damage by excess production of reactive oxygen species. However, it is unknown whether ischemic accumulation of succinate affects neural stem cell proliferation. In this study, we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery. We found that succinate levels increased in serum and brain tissue(cortex and hippocampus) after ischemia/reperfusion injury. Oxygen-glucose deprivation and reoxygenation stimulated primary neural stem cells to produce abundant succinate. Succinate can be converted into diethyl succinate in cells. Exogenous diethyl succinate inhibited the proliferation of mouse-derived C17.2 neural stem cells and increased the infarct volume in the rat model of cerebral ischemia/reperfusion injury. Exogenous diethyl succinate also increased the succinylation of the Rho family GTPase Cdc42 but repressed Cdc42 GTPase activity in C17.2 cells. Increasing Cdc42 succinylation by knockdown of the desuccinylase Sirt5 also inhibited Cdc42 GTPase activity in C17.2 cells. Our findings suggest that ischemic accumulation of succinate decreases Cdc42 GTPase activity by induction of Cdc42 succinylation, which inhibits the proliferation of neural stem cells and aggravates cerebral ischemia/reperfusion injury.展开更多
Phase-sensitive optical time-domain reflectometry(Φ-OTDR)has attracted numerous attention due to its superior performance in detecting the weak perturbations along the fiber.Relying on the ultra-sensitivity of light ...Phase-sensitive optical time-domain reflectometry(Φ-OTDR)has attracted numerous attention due to its superior performance in detecting the weak perturbations along the fiber.Relying on the ultra-sensitivity of light phase to the tiny deformation of optical fiber,Φ-OTDR has been treated as a powerful technique with a wide range of applications.It is fundamental to extract the phase of scattering light wave accurately and the methods include coherent detection,I/Q demodulation,3 by 3 coupler,dual probe pulses,and so on.Meanwhile,researchers have also made great efforts to improve the performance ofΦ-OTDR.The frequency response range,the measurement accuracy,the sensing distance,the spatial resolution,and the accuracy of event discrimination,all have been enhanced by various techniques.Furthermore,lots of researches on the applications in various kinds of fields have been carried out,where certain modifications and techniques have been developed.Therefore,Φ-OTDR remains as a booming technique in both researches and applications.展开更多
The strong texture of Mg alloys can lead to strong tension–compression yield asymmetry and corrosion anisotropy,and this will consequently affect the effectiveness of hard tissue implants.A biomedical Mg–6Zn–0.5Zr ...The strong texture of Mg alloys can lead to strong tension–compression yield asymmetry and corrosion anisotropy,and this will consequently affect the effectiveness of hard tissue implants.A biomedical Mg–6Zn–0.5Zr alloy containing a large number of{1012}primary twins and{1012}–{1012}secondary twins is successfully prepared by cross compression.The dual twin structure not only removes the tension–compression yield asymmetry completely,but effectively reduces the corrosion anisotropy without compromise of corrosion resistance.The difference between the largest corrosion rate and smallest one is~1.2 times compared to~1.6 times of the original materials.It is found that the reduced corrosion anisotropy is related to re-distribution of crystallographic orientations by twins.展开更多
General-purpose plastics with high strength and toughness have been in great demand for structural engineering applications.To achieve the reinforcement and broaden the application scope of high-density polyethylene(H...General-purpose plastics with high strength and toughness have been in great demand for structural engineering applications.To achieve the reinforcement and broaden the application scope of high-density polyethylene(HDPE),multi-flow vibration injection molding(MFVIM)and ultrahigh molecular weight polyethylene(UHMWPE)are synergistically employed in this work.Herein,the MFVIM has better shear layer control ability and higher fabrication advantage for complex parts than other analogous novel injection molding technologies reported.The reinforcing effect of various filling times and UHMWPE contents as well as the corresponding microstructure evolution are investigated.When 5 wt%UHMWPE is added,MFVIM process with six flow times thickens the shear layer to the whole thickness.The tensile strength and modulus increase to 2.14 and 1.39 times,respectively,compared to neat HDPE on the premise of remaining 70%impact strength.Structural characterizations indicate that the enhancement is attributed to the improvement of shish-kebab content and lamellae compactness,as well as related to the corresponding size distributions of undissolved UHMWPE particles.This novel injection molding technology with great industrial prospects provides a facile and effective strategy to broaden the engineering applications of HDPE materials.Besides,excessive UHMWPE may impair the synergistic enhancement effect,which is also reasonably explained.展开更多
基金supported by the National Natural Science Foundation of China,No. 81671164 (to SHQ)the Natural Science Foundation of Jiangsu Province of China,No. BK20211348 (to SHQ)Xuzhou Basic Research Program,No. KC21030 (to LYH)。
文摘Ischemic accumulation of succinate causes cerebral damage by excess production of reactive oxygen species. However, it is unknown whether ischemic accumulation of succinate affects neural stem cell proliferation. In this study, we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery. We found that succinate levels increased in serum and brain tissue(cortex and hippocampus) after ischemia/reperfusion injury. Oxygen-glucose deprivation and reoxygenation stimulated primary neural stem cells to produce abundant succinate. Succinate can be converted into diethyl succinate in cells. Exogenous diethyl succinate inhibited the proliferation of mouse-derived C17.2 neural stem cells and increased the infarct volume in the rat model of cerebral ischemia/reperfusion injury. Exogenous diethyl succinate also increased the succinylation of the Rho family GTPase Cdc42 but repressed Cdc42 GTPase activity in C17.2 cells. Increasing Cdc42 succinylation by knockdown of the desuccinylase Sirt5 also inhibited Cdc42 GTPase activity in C17.2 cells. Our findings suggest that ischemic accumulation of succinate decreases Cdc42 GTPase activity by induction of Cdc42 succinylation, which inhibits the proliferation of neural stem cells and aggravates cerebral ischemia/reperfusion injury.
基金supported in part by the Startup Fund from Southern University of Science and Technology and Shenzhen government under Grant No.Y01236128by the National Natural Science Foundation of China(NSFC)under Grant Nos.61627816 and 61975076by the Qing Lan Project of Jiangsu Province。
文摘Phase-sensitive optical time-domain reflectometry(Φ-OTDR)has attracted numerous attention due to its superior performance in detecting the weak perturbations along the fiber.Relying on the ultra-sensitivity of light phase to the tiny deformation of optical fiber,Φ-OTDR has been treated as a powerful technique with a wide range of applications.It is fundamental to extract the phase of scattering light wave accurately and the methods include coherent detection,I/Q demodulation,3 by 3 coupler,dual probe pulses,and so on.Meanwhile,researchers have also made great efforts to improve the performance ofΦ-OTDR.The frequency response range,the measurement accuracy,the sensing distance,the spatial resolution,and the accuracy of event discrimination,all have been enhanced by various techniques.Furthermore,lots of researches on the applications in various kinds of fields have been carried out,where certain modifications and techniques have been developed.Therefore,Φ-OTDR remains as a booming technique in both researches and applications.
基金supported by the National Natural Science Foundation of China(Nos.52101132,51871032 and 51901202)the Natural Science Foundation of Jiangsu Province(No.BK20202010)+1 种基金the Basic and Applied Basic Research Project of Guangzhou(202201011250)the City University of Hong Kong Strategic Research Grant(No.7005264).
文摘The strong texture of Mg alloys can lead to strong tension–compression yield asymmetry and corrosion anisotropy,and this will consequently affect the effectiveness of hard tissue implants.A biomedical Mg–6Zn–0.5Zr alloy containing a large number of{1012}primary twins and{1012}–{1012}secondary twins is successfully prepared by cross compression.The dual twin structure not only removes the tension–compression yield asymmetry completely,but effectively reduces the corrosion anisotropy without compromise of corrosion resistance.The difference between the largest corrosion rate and smallest one is~1.2 times compared to~1.6 times of the original materials.It is found that the reduced corrosion anisotropy is related to re-distribution of crystallographic orientations by twins.
基金by the National Natural Science Foundation of China(No.21627804).
文摘General-purpose plastics with high strength and toughness have been in great demand for structural engineering applications.To achieve the reinforcement and broaden the application scope of high-density polyethylene(HDPE),multi-flow vibration injection molding(MFVIM)and ultrahigh molecular weight polyethylene(UHMWPE)are synergistically employed in this work.Herein,the MFVIM has better shear layer control ability and higher fabrication advantage for complex parts than other analogous novel injection molding technologies reported.The reinforcing effect of various filling times and UHMWPE contents as well as the corresponding microstructure evolution are investigated.When 5 wt%UHMWPE is added,MFVIM process with six flow times thickens the shear layer to the whole thickness.The tensile strength and modulus increase to 2.14 and 1.39 times,respectively,compared to neat HDPE on the premise of remaining 70%impact strength.Structural characterizations indicate that the enhancement is attributed to the improvement of shish-kebab content and lamellae compactness,as well as related to the corresponding size distributions of undissolved UHMWPE particles.This novel injection molding technology with great industrial prospects provides a facile and effective strategy to broaden the engineering applications of HDPE materials.Besides,excessive UHMWPE may impair the synergistic enhancement effect,which is also reasonably explained.
