In this paper,the dynamical behavior of a reaction-diffusion system with quiescence in a closed environment is investigated.The global existence of the solution is obtained by the upper and lower solution method,and t...In this paper,the dynamical behavior of a reaction-diffusion system with quiescence in a closed environment is investigated.The global existence of the solution is obtained by the upper and lower solution method,and the dissipative structure of the system is derived by constructing Lyapunov functions.展开更多
The concentration of sodium chloride is of prime importance in the initiation and reversal of sperm quiescence inthe cauda epididymis. Other factors such as inorganic and organic constituents of the luminal fluid are ...The concentration of sodium chloride is of prime importance in the initiation and reversal of sperm quiescence inthe cauda epididymis. Other factors such as inorganic and organic constituents of the luminal fluid are of secondary im-portance and might assist in inducing sperm quiescence. (Asian J Androl 2001; 3; 181 — 183 )展开更多
Quiescent state has been observed in stem cells(SCs),including in adult SCs and in cancer SCs(CSCs).Quiescent status of SCs contributes to SC self-renewal and conduces to averting SC death from harsh external stimuli....Quiescent state has been observed in stem cells(SCs),including in adult SCs and in cancer SCs(CSCs).Quiescent status of SCs contributes to SC self-renewal and conduces to averting SC death from harsh external stimuli.In this review,we provide an overview of intrinsic mechanisms and extrinsic factors that regulate adult SC quiescence.The intrinsic mechanisms discussed here include the cell cycle,mitogenic signaling,Notch signaling,epigenetic modification,and metabolism and transcriptional regulation,while the extrinsic factors summarized here include microenvironment cells,extracellular factors,and immune response and inflammation in microenvironment.Quiescent state of CSCs has been known to contribute immensely to therapeutic resistance in multiple cancers.The characteristics and the regulation mechanisms of quiescent CSCs are discussed in detail.Importantly,we also outline the recent advances and controversies in therapeutic strategies targeting CSC quiescence.展开更多
Background: The time-related decline in regenerative capacity and organ homeostasis is a major feature of aging. Rehmannia glutinosa and Astragalus membranaceus have been used as traditional Chinese herbal medicines f...Background: The time-related decline in regenerative capacity and organ homeostasis is a major feature of aging. Rehmannia glutinosa and Astragalus membranaceus have been used as traditional Chinese herbal medicines for enhanced immunity and prolonged life. However, the mechanism by which this herbal medicine slows aging is unknown. In this study, we investigated the mechanism of the herbal anti-aging effect.Methods: Mice were fed diets supplemented with R. glutinosa or A. membranaceus for 10 months; the control group was fed a standard diet. The phenotypes were evaluated using a grading score system and survival analysis. The percentages of the senescence phenotypes of hematopoietic stem cells(HSCs) were determined by fluorescence-activated cell sorting analysis. The function and the mechanism of HSCs were analyzed by clonogenic assay and the real-time polymerase chain reaction.Results: The anti-aging effect of R. glutinosa is due to the enhanced function of HSCs. Mice fed with R. glutinosa displayed characteristics of a slowed aging process,including decreased senescence and increased rate of survival. Flow cytometry analysis showed decreased numbers of Lin–Sca1^+c-kit–(LSK) cells, long-term HSCs(LT-HSCs) and short-term HSCs(ST-HSCs) in the R. glutinosa group. In vitro, clonogenic assays showed increased self-renewal ability of LT-HSCs from the R. glutinosa group as well as maintaining LSK quiescence through upregulated p18 expression. The R. glutinosa group also showed decreased reactive oxygen species levels and the percentage of β-gal^+ cells through downregulation of the cellular senescence-associated protein p53 and p16.Conclusion: Rehmannia glutinosa exerts anti-aging effects by maintaining the quiescence and decreasing the senescence of HSCs.展开更多
The September 21, 1999, Jiji （Chi-Chi） Mw7.6 earthquake is the strongest event occurred since 1900 in Taiwan of China. It is located in the middle segment of the western seismic zone of Taiwan. Based on several vers...The September 21, 1999, Jiji （Chi-Chi） Mw7.6 earthquake is the strongest event occurred since 1900 in Taiwan of China. It is located in the middle segment of the western seismic zone of Taiwan. Based on several versions of China earthquake catalogue this study found that a seismic gap of M≥5 earthquakes appeared, in and around the epicenter region, 24 years before and lasted up to the mainshock occurrence. This study also noticed that there existed a lager seismically quiet region of M≥4 earthquakes, which lasted for about 2.5 years before the mainshock occurrence, The spatial variation pattern of regional seismicity before the mainshock seems to match with its coseismic source rupture process. The mentioned seismicity gap and seismic quiescence might be an indication of the preparation process of the Jiji strong earthquake.展开更多
Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M_≥6 occurred means more elastic energy store and speedy energy accumulation there. When...Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M_≥6 occurred means more elastic energy store and speedy energy accumulation there. When an active period of big earthquake activity appeared in wide region, in the place where earthquake (M_≥6) occurred in the past quiet period, the big earthquake with magnitude of 7 or more often occur there. We call the above-mentioned judgement for predicting big earthquake the 'criterion of activity in quiescence'. The criterion is relatively effective for predicting location of big earthquake. In general, error of predicting epicenter is no more than 100 km. According to the criterion, we made successfully a middle-term prediction on the 1996 Lijiang earthquake in Yunnan Province, the error of predicted location is about 50 km. Besides, the 1994 Taiwan strait earthquake (M_s=7.3), the 1995 Yunnan-Myanmar boundary earthquake (M_s=7.2) and the Mani earthquake (M_s=7.9) in north Tibet are accordant with the retrospective predictions by the 'criterion of activity in quiescence'. The windows of 'activity in quiescence' identified statistically by us are 1940-1945, 1958-1961 and 1979-1986. Using the 'criterion of activity in quiescence' to predict big earthquake in the mainland of China,the earthquake defined by 'activity in quiescence' has magnitude of 6 or more; For the Himalayas seismic belt, the Pacific seismic belt and the north-west boundary seismic belt of Xinjiang, the earthquake defined by 'activity in quiescence' has magnitude of 7, which is corresponding to earthquake with magnitude of much more than 7 in future. For the regions where there are not tectonically and historically a possibility of occurring big earthquake (M_s=7), the criterion of activity in quiescence is not effective.展开更多
文摘In this paper,the dynamical behavior of a reaction-diffusion system with quiescence in a closed environment is investigated.The global existence of the solution is obtained by the upper and lower solution method,and the dissipative structure of the system is derived by constructing Lyapunov functions.
文摘The concentration of sodium chloride is of prime importance in the initiation and reversal of sperm quiescence inthe cauda epididymis. Other factors such as inorganic and organic constituents of the luminal fluid are of secondary im-portance and might assist in inducing sperm quiescence. (Asian J Androl 2001; 3; 181 — 183 )
文摘Quiescent state has been observed in stem cells(SCs),including in adult SCs and in cancer SCs(CSCs).Quiescent status of SCs contributes to SC self-renewal and conduces to averting SC death from harsh external stimuli.In this review,we provide an overview of intrinsic mechanisms and extrinsic factors that regulate adult SC quiescence.The intrinsic mechanisms discussed here include the cell cycle,mitogenic signaling,Notch signaling,epigenetic modification,and metabolism and transcriptional regulation,while the extrinsic factors summarized here include microenvironment cells,extracellular factors,and immune response and inflammation in microenvironment.Quiescent state of CSCs has been known to contribute immensely to therapeutic resistance in multiple cancers.The characteristics and the regulation mechanisms of quiescent CSCs are discussed in detail.Importantly,we also outline the recent advances and controversies in therapeutic strategies targeting CSC quiescence.
基金National Science Foundation for China,Grant/Award Number:31672374PUMC Youth Fund,Grant/Award Number:2017310018CAMS Innovation Fund for Medical Sciences,Grant/Award Number:2016-12M-1-012
文摘Background: The time-related decline in regenerative capacity and organ homeostasis is a major feature of aging. Rehmannia glutinosa and Astragalus membranaceus have been used as traditional Chinese herbal medicines for enhanced immunity and prolonged life. However, the mechanism by which this herbal medicine slows aging is unknown. In this study, we investigated the mechanism of the herbal anti-aging effect.Methods: Mice were fed diets supplemented with R. glutinosa or A. membranaceus for 10 months; the control group was fed a standard diet. The phenotypes were evaluated using a grading score system and survival analysis. The percentages of the senescence phenotypes of hematopoietic stem cells(HSCs) were determined by fluorescence-activated cell sorting analysis. The function and the mechanism of HSCs were analyzed by clonogenic assay and the real-time polymerase chain reaction.Results: The anti-aging effect of R. glutinosa is due to the enhanced function of HSCs. Mice fed with R. glutinosa displayed characteristics of a slowed aging process,including decreased senescence and increased rate of survival. Flow cytometry analysis showed decreased numbers of Lin–Sca1^+c-kit–(LSK) cells, long-term HSCs(LT-HSCs) and short-term HSCs(ST-HSCs) in the R. glutinosa group. In vitro, clonogenic assays showed increased self-renewal ability of LT-HSCs from the R. glutinosa group as well as maintaining LSK quiescence through upregulated p18 expression. The R. glutinosa group also showed decreased reactive oxygen species levels and the percentage of β-gal^+ cells through downregulation of the cellular senescence-associated protein p53 and p16.Conclusion: Rehmannia glutinosa exerts anti-aging effects by maintaining the quiescence and decreasing the senescence of HSCs.
文摘The September 21, 1999, Jiji （Chi-Chi） Mw7.6 earthquake is the strongest event occurred since 1900 in Taiwan of China. It is located in the middle segment of the western seismic zone of Taiwan. Based on several versions of China earthquake catalogue this study found that a seismic gap of M≥5 earthquakes appeared, in and around the epicenter region, 24 years before and lasted up to the mainshock occurrence. This study also noticed that there existed a lager seismically quiet region of M≥4 earthquakes, which lasted for about 2.5 years before the mainshock occurrence, The spatial variation pattern of regional seismicity before the mainshock seems to match with its coseismic source rupture process. The mentioned seismicity gap and seismic quiescence might be an indication of the preparation process of the Jiji strong earthquake.
基金State Natural Science Foundation of China!(49674210).
文摘Earthquake activities in history are characterized by active and quiet periods. In the quiet period, the place where earthquake M_≥6 occurred means more elastic energy store and speedy energy accumulation there. When an active period of big earthquake activity appeared in wide region, in the place where earthquake (M_≥6) occurred in the past quiet period, the big earthquake with magnitude of 7 or more often occur there. We call the above-mentioned judgement for predicting big earthquake the 'criterion of activity in quiescence'. The criterion is relatively effective for predicting location of big earthquake. In general, error of predicting epicenter is no more than 100 km. According to the criterion, we made successfully a middle-term prediction on the 1996 Lijiang earthquake in Yunnan Province, the error of predicted location is about 50 km. Besides, the 1994 Taiwan strait earthquake (M_s=7.3), the 1995 Yunnan-Myanmar boundary earthquake (M_s=7.2) and the Mani earthquake (M_s=7.9) in north Tibet are accordant with the retrospective predictions by the 'criterion of activity in quiescence'. The windows of 'activity in quiescence' identified statistically by us are 1940-1945, 1958-1961 and 1979-1986. Using the 'criterion of activity in quiescence' to predict big earthquake in the mainland of China,the earthquake defined by 'activity in quiescence' has magnitude of 6 or more; For the Himalayas seismic belt, the Pacific seismic belt and the north-west boundary seismic belt of Xinjiang, the earthquake defined by 'activity in quiescence' has magnitude of 7, which is corresponding to earthquake with magnitude of much more than 7 in future. For the regions where there are not tectonically and historically a possibility of occurring big earthquake (M_s=7), the criterion of activity in quiescence is not effective.
