The size effect can be attributed to the relative importance of growth options versus assets-in-place in total assets.By incorporating the changing trend of growth options over firm lifecycle into the dynamic investme...The size effect can be attributed to the relative importance of growth options versus assets-in-place in total assets.By incorporating the changing trend of growth options over firm lifecycle into the dynamic investment model developed by Berk et al.(1999)。this paper demonstrates that the gradual exhausting or exercising of growth options would cause a downward pattern of size effect over firm lifecycle,while new growth options created by R&D or innovative investments can intensify size effect.Using a sample of listed firms in USA stock market during the period of 1963-2018,both cross-sectional evidence on individual stocks and time-series evidence on portfolios analysis support theoretical preditions well,and empirical findings are robust for different methodologies,different measures of the exerci sing/creating of growth options,and for China's stock market.展开更多
Tumor growth and metastasis depend on the establishment of tumor vasculature to provide oxygen,nutrients,and other essential factors.The well-known vascular endothelial growth factor(VEGF) signaling is crucial for spr...Tumor growth and metastasis depend on the establishment of tumor vasculature to provide oxygen,nutrients,and other essential factors.The well-known vascular endothelial growth factor(VEGF) signaling is crucial for sprouting angiogenesis as well as recruitment of circulating progenitor endothelial cells to tumor vasculature,which has become therapeutic targets in clinical practice.However,the survival benefits gained from targeting VEGF signaling have been very limited,with the inevitable development of treatment resistance.In this article,we discuss the most recent findings and understanding on how solid tumors evade VEGF-targeted therapy,with a special focus on vessel co-option,vessel remodeling,and tumor cell-derived vasculature establishment.Vessel co-option may occur in tumors independently of sprouting angiogenesis,and sprouting angiogenesis is not always required for tumor growth.The differences between vessel-like structure and tubule-like structure formed by tumor cells are also introduced.The exploration of the underlying mechanisms of these alternative angiogenic approaches would not only widen our knowledge of tumor angiogenesis but also provide novel therapeutic targets for better controlling cancer growth and metastasis.展开更多
基金from National Natural Science Foundationof China(Grant No.of 71472025 and 71972027)the Fundfor Cultural Celebrity and Talents(Grant No.of[2015]49)and the Characteristic Innovation Projects of Colleges and Universities in Guangdong Province(Grant No.2019KTSCX036)are gratefully acknowledged.
文摘The size effect can be attributed to the relative importance of growth options versus assets-in-place in total assets.By incorporating the changing trend of growth options over firm lifecycle into the dynamic investment model developed by Berk et al.(1999)。this paper demonstrates that the gradual exhausting or exercising of growth options would cause a downward pattern of size effect over firm lifecycle,while new growth options created by R&D or innovative investments can intensify size effect.Using a sample of listed firms in USA stock market during the period of 1963-2018,both cross-sectional evidence on individual stocks and time-series evidence on portfolios analysis support theoretical preditions well,and empirical findings are robust for different methodologies,different measures of the exerci sing/creating of growth options,and for China's stock market.
基金supported by grants from the National Natural Science Foundation of China(No.81472386,81472380,81272340,and 81030043)the National High Technology Research and Development Program of China (863 Program,No.2012AA02A501)
文摘Tumor growth and metastasis depend on the establishment of tumor vasculature to provide oxygen,nutrients,and other essential factors.The well-known vascular endothelial growth factor(VEGF) signaling is crucial for sprouting angiogenesis as well as recruitment of circulating progenitor endothelial cells to tumor vasculature,which has become therapeutic targets in clinical practice.However,the survival benefits gained from targeting VEGF signaling have been very limited,with the inevitable development of treatment resistance.In this article,we discuss the most recent findings and understanding on how solid tumors evade VEGF-targeted therapy,with a special focus on vessel co-option,vessel remodeling,and tumor cell-derived vasculature establishment.Vessel co-option may occur in tumors independently of sprouting angiogenesis,and sprouting angiogenesis is not always required for tumor growth.The differences between vessel-like structure and tubule-like structure formed by tumor cells are also introduced.The exploration of the underlying mechanisms of these alternative angiogenic approaches would not only widen our knowledge of tumor angiogenesis but also provide novel therapeutic targets for better controlling cancer growth and metastasis.
