Study on the fossil plants and the palynological assemblage is the basic botanical research on the coal bearing strata. The practice indicate that comprehensive data from the study on the fusinized wood fossil, the ph...Study on the fossil plants and the palynological assemblage is the basic botanical research on the coal bearing strata. The practice indicate that comprehensive data from the study on the fusinized wood fossil, the phyterals and the analysis of dispersed cuticles will effectively improve the level of the study on the coal bearing strata as a whole.展开更多
Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied...Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO2 concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research. However, for plants with originally thin and fragile cuticles, e.g., most deciduous plants, conventional techniques sometimes fail to obtain cuticular membranes with sufficient size, or sometimes unable to recover any. This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo- climatological research. Here, we describe a new method using clear nail polish as a medium to ＂strengthen＂ the originally thin and fragile cuticles prior to maceration procedures. We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature. Metasequoia, with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre- sentative, 114. glyptostroboides, as a comparative reference, bas been widely used as a model genus for the study of evolution of plants, palaeoclimatological reconstruction, and plant adaptation to climate changes. But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process. The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.展开更多
The human cornea is exposed directly to particulate matter （PM） in polluted air. This exposure can cause eye discomfort and corneal injury. Ultrafine PM （diameter ~100 nm） is thought to be particularly harmful to ...The human cornea is exposed directly to particulate matter （PM） in polluted air. This exposure can cause eye discomfort and corneal injury. Ultrafine PM （diameter ~100 nm） is thought to be particularly harmful to health, but there is limited research investigating its toxicity to the eye. In this study, we evaluated toxiciW differences among 30-, 40-, 100- and 150-nm silicon dioxide nanoparticles （Si02 NPs） on the cornea. A 24-hour in vitro exposure of primary human corneal epithelial cells （hCECs） to ultrafine （30 and 40 nm） SiO2 NPs produced toxicity, as evidenced by cell membrane damage, reduced cell viability, increased cell death and mitochondrial dysfunction. In vivo exposure to the same nanoparticles produced observable corneal injury. These effects were more severe with ultrafine than with fine （100 and 150 nm） Si02 NPs. Common antioxidant compounds, e.g., glutathione, did not protect the cornea from SiO2 NP-induced damage. However, foetal bovine serum （FBS） did significantly reduce toxicity, likely by forming a protective protein corona around the nanoparticles. This finding suggests that FBS （or its derivatives） may be a useful clinical therapy for corneal toxicity caused by ultrafine particulates.展开更多
文摘Study on the fossil plants and the palynological assemblage is the basic botanical research on the coal bearing strata. The practice indicate that comprehensive data from the study on the fusinized wood fossil, the phyterals and the analysis of dispersed cuticles will effectively improve the level of the study on the coal bearing strata as a whole.
基金supported by CAS/SAFEA International Partnership Program for Creative Research Teams,the Pilot Project of Knowledge Innovation of CAS (Grant No. KZCX2-YW-105)National Basic Research Program of China (Grant No. 2006CB806400)National Natural Science Foundation of China (Grant Nos. 40402002,40872011)
文摘Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO2 concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research. However, for plants with originally thin and fragile cuticles, e.g., most deciduous plants, conventional techniques sometimes fail to obtain cuticular membranes with sufficient size, or sometimes unable to recover any. This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo- climatological research. Here, we describe a new method using clear nail polish as a medium to ＂strengthen＂ the originally thin and fragile cuticles prior to maceration procedures. We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature. Metasequoia, with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre- sentative, 114. glyptostroboides, as a comparative reference, bas been widely used as a model genus for the study of evolution of plants, palaeoclimatological reconstruction, and plant adaptation to climate changes. But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process. The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.
基金supported by the National Key R&D program of China(2018YFA0107302,2016YFA0201600)the National Natural Science Foundation of China(81570890)the Foundation of Southwest Hospital(SWH2016LHYS-03)
文摘The human cornea is exposed directly to particulate matter （PM） in polluted air. This exposure can cause eye discomfort and corneal injury. Ultrafine PM （diameter ~100 nm） is thought to be particularly harmful to health, but there is limited research investigating its toxicity to the eye. In this study, we evaluated toxiciW differences among 30-, 40-, 100- and 150-nm silicon dioxide nanoparticles （Si02 NPs） on the cornea. A 24-hour in vitro exposure of primary human corneal epithelial cells （hCECs） to ultrafine （30 and 40 nm） SiO2 NPs produced toxicity, as evidenced by cell membrane damage, reduced cell viability, increased cell death and mitochondrial dysfunction. In vivo exposure to the same nanoparticles produced observable corneal injury. These effects were more severe with ultrafine than with fine （100 and 150 nm） Si02 NPs. Common antioxidant compounds, e.g., glutathione, did not protect the cornea from SiO2 NP-induced damage. However, foetal bovine serum （FBS） did significantly reduce toxicity, likely by forming a protective protein corona around the nanoparticles. This finding suggests that FBS （or its derivatives） may be a useful clinical therapy for corneal toxicity caused by ultrafine particulates.
