Poly(_(L)-lactide)(PLLA),a leading biodegradable polyester,has demonstrated potential as a sustainable alternative,owing to its excellent biodegradability and rigidity.However,their slow crystallization kinetics and p...Poly(_(L)-lactide)(PLLA),a leading biodegradable polyester,has demonstrated potential as a sustainable alternative,owing to its excellent biodegradability and rigidity.However,their slow crystallization kinetics and poor heat resistance limit their application scope.Recent advances have highlighted that the combination of extensional flow and thermal fields can achieve toughness–stiffness balance,high transparency,and good heat resistance.However,the effect of extensional flow on the post-non-isothermal crystallization of PLLA during heating and the resulting crystalline texture remains unclear.In this study,PLLA with a heterogeneous amorphous structure and oriented polymorph was prepared by extensional flow.The effect of heterogeneous amorphous structures on non-isothermal crystallization kinetics during the heating process was studied by thermal analysis,polarized optical microscopy,infrared spectroscopy,and ex situ/in situ X-ray characterization.These results clearly illustrate that extensional flow enhances the formation of oriented crystalline structures,accelerates non-isothermal crystallization,and modulates the polymorphic composition of PLLA.Moreover,an unexpected dual cold-crystallization behavior is identified in ordered PLLA samples upon extensional flow,which is from the extensional flow-induced heterogeneous amorphous phase into α' phase(low-temperature peak)and the pristine amorphous phase intoαphase(high-temperature peak).The extensional flow primarily promotes the formation of the more perfectαandα'phases,but has a negative effect on the final content ofαphase formed after cold crystallization andα'-to-αphase transformation.The findings of this work advance the understanding of PLLA non-isothermal crystallization after extensional flow and offer valuable guidance for high-performance PLLA upon heat treatment in practical processing.展开更多
AIM： To investigate matrix metalloproteinases（MMPs）and tissue inhibitor of metalloproteinases（TIMPs）expression during the progress of fusarium solani（F.solani） keratitis in a rat model.· METHODS： A rat mo...AIM： To investigate matrix metalloproteinases（MMPs）and tissue inhibitor of metalloproteinases（TIMPs）expression during the progress of fusarium solani（F.solani） keratitis in a rat model.· METHODS： A rat model of F.solani keratitis was produced using corneal scarification and a hand-made contact lens. MMPs and TIMPs expressiond were explored in this rat model of F.solani keratitis using real-time polymerase chain reaction（PCR） and DIF.GM6001（400 μmol/m L） was used to treat infected corneas. The keratitis duration, amount and area of corneal neovascularization（CNV） were evaluated.·RESULTS： MMP-3 expression was 66.3 times higher in infected corneas compared to normal corneas. MMP-8,-9,and-13 expressions were significantly upregulated in the mid-period of the infection, with infected- to-normal ratios of 4.03, 39.86, and 5.94, respectively. MMP-2 and-7expressions increased in the late period, with the infected-to-normal ratios of 5.94 and 16.22, respectively.TIMP-1 expression was upregulated in the early period,and it was 43.17 times higher in infected compared to normal corneas, but TIMP-2,-3, and-4 expressions were mildly downregulated or unchanged. The results of DIF were consistent with the result of real-time PCR.GM6001, a MMPs inhibitor, decreased the duration of F.solani infection and the amount and area of CNV.·CONCLUSION： MMPs and TIMPs contributed into the progress of F.solani keratitis.展开更多
Dear Sir,I am Dr. Xiao-Qiang Liu, from the Department of Ophthalmology, Shanghai Tenth People’s Hospital,Tongji University School of Medicine, Shanghai, China. I write to report a case of malignant hypertensive retin...Dear Sir,I am Dr. Xiao-Qiang Liu, from the Department of Ophthalmology, Shanghai Tenth People’s Hospital,Tongji University School of Medicine, Shanghai, China. I write to report a case of malignant hypertensive retinopathy demonstrated by spectral domain optical coherence展开更多
基金supported by the National Natural Science Foundation of China(Nos.U23A20583,52033005,U21A2090,and 52173040)Department of Science and Technology of Sichuan Province(No.2024NSFTD0003)。
文摘Poly(_(L)-lactide)(PLLA),a leading biodegradable polyester,has demonstrated potential as a sustainable alternative,owing to its excellent biodegradability and rigidity.However,their slow crystallization kinetics and poor heat resistance limit their application scope.Recent advances have highlighted that the combination of extensional flow and thermal fields can achieve toughness–stiffness balance,high transparency,and good heat resistance.However,the effect of extensional flow on the post-non-isothermal crystallization of PLLA during heating and the resulting crystalline texture remains unclear.In this study,PLLA with a heterogeneous amorphous structure and oriented polymorph was prepared by extensional flow.The effect of heterogeneous amorphous structures on non-isothermal crystallization kinetics during the heating process was studied by thermal analysis,polarized optical microscopy,infrared spectroscopy,and ex situ/in situ X-ray characterization.These results clearly illustrate that extensional flow enhances the formation of oriented crystalline structures,accelerates non-isothermal crystallization,and modulates the polymorphic composition of PLLA.Moreover,an unexpected dual cold-crystallization behavior is identified in ordered PLLA samples upon extensional flow,which is from the extensional flow-induced heterogeneous amorphous phase into α' phase(low-temperature peak)and the pristine amorphous phase intoαphase(high-temperature peak).The extensional flow primarily promotes the formation of the more perfectαandα'phases,but has a negative effect on the final content ofαphase formed after cold crystallization andα'-to-αphase transformation.The findings of this work advance the understanding of PLLA non-isothermal crystallization after extensional flow and offer valuable guidance for high-performance PLLA upon heat treatment in practical processing.
基金Supported by Tongji University,Shanghai,China(No.2012KJ042)
文摘AIM： To investigate matrix metalloproteinases（MMPs）and tissue inhibitor of metalloproteinases（TIMPs）expression during the progress of fusarium solani（F.solani） keratitis in a rat model.· METHODS： A rat model of F.solani keratitis was produced using corneal scarification and a hand-made contact lens. MMPs and TIMPs expressiond were explored in this rat model of F.solani keratitis using real-time polymerase chain reaction（PCR） and DIF.GM6001（400 μmol/m L） was used to treat infected corneas. The keratitis duration, amount and area of corneal neovascularization（CNV） were evaluated.·RESULTS： MMP-3 expression was 66.3 times higher in infected corneas compared to normal corneas. MMP-8,-9,and-13 expressions were significantly upregulated in the mid-period of the infection, with infected- to-normal ratios of 4.03, 39.86, and 5.94, respectively. MMP-2 and-7expressions increased in the late period, with the infected-to-normal ratios of 5.94 and 16.22, respectively.TIMP-1 expression was upregulated in the early period,and it was 43.17 times higher in infected compared to normal corneas, but TIMP-2,-3, and-4 expressions were mildly downregulated or unchanged. The results of DIF were consistent with the result of real-time PCR.GM6001, a MMPs inhibitor, decreased the duration of F.solani infection and the amount and area of CNV.·CONCLUSION： MMPs and TIMPs contributed into the progress of F.solani keratitis.
文摘Dear Sir,I am Dr. Xiao-Qiang Liu, from the Department of Ophthalmology, Shanghai Tenth People’s Hospital,Tongji University School of Medicine, Shanghai, China. I write to report a case of malignant hypertensive retinopathy demonstrated by spectral domain optical coherence
