The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rat...The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena.展开更多
In some clinical applications in oncology randomized, double armed, and double-blind trials are not possible. In case of device applications, double-blinded conditions are nonrealistic, and with many times the randomi...In some clinical applications in oncology randomized, double armed, and double-blind trials are not possible. In case of device applications, double-blinded conditions are nonrealistic, and with many times the randomization also has complications due to the high-line treatments where the reference cohort is not available;the active “arm” has mainly palliative initiative. Sometimes highly personalized therapies block the collection of the homogeneous group and limit its double-arm randomization. Our objective is to discuss the situations of the single arm evaluation and to give methods for the mining of information from this to increase the level of evidence of the measured dataset. The basic idea of the data-separation is the appropriate parameterization of the non-parametric Kaplan-Meier survival pattern by the poly-Weibull fit.展开更多
Studying the dynamics of plant populations is crucial to the conservation and management of endangered plants.The diameter at breast height(DBH),tree height,crown width,and environmental factors of a total of 15 plots...Studying the dynamics of plant populations is crucial to the conservation and management of endangered plants.The diameter at breast height(DBH),tree height,crown width,and environmental factors of a total of 15 plots in five populations in Guizhou Province,China were measured in this study.The method of substituting diameter at breast height for age was used to divide the population into 7 age classes.The age structure,static life table,and relationship between the population characteristics and environmental factors of the Litsea coreana Levl.var.sinensis population were studied.Moreover,the time series model was used to predict the population dynamics.Results showed that the age structure of population in Zhengan County(Population ZA)had an inverted Jshape with abundant seedlings and insufficient middle-aged and elderly individuals.The age structures of populations in Daozhen County(Population DZ),Kaiyang County(KY),Meitan County(Population MT),and Xishui County(Population XS)were spindle-shaped with few young individuals and many middle-aged and elderly individuals.The mortality rate of each population fluctuated with the increase in age class,and the populations were extremely unstable.The survival curve was close to the Deevey III type,and the degree of deviation was related to the lack of young individuals.After the age stages II,IV,and VI,the number of aged plants in the different populations initially increased then decreased,and population stability was difficult to maintain.Redundancy analysis showed that the DBH,tree height and crown width of the population decreased with the increase of annual mean temperature,and the population density was restricted by soil nutrient conditions to a certain extent.The results of this work provide scientific basis for the conservation and sustainable utilization of natural populations of L.coreana var.sinensis in Guizhou Province,China.展开更多
文摘The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena.
文摘In some clinical applications in oncology randomized, double armed, and double-blind trials are not possible. In case of device applications, double-blinded conditions are nonrealistic, and with many times the randomization also has complications due to the high-line treatments where the reference cohort is not available;the active “arm” has mainly palliative initiative. Sometimes highly personalized therapies block the collection of the homogeneous group and limit its double-arm randomization. Our objective is to discuss the situations of the single arm evaluation and to give methods for the mining of information from this to increase the level of evidence of the measured dataset. The basic idea of the data-separation is the appropriate parameterization of the non-parametric Kaplan-Meier survival pattern by the poly-Weibull fit.
基金supported by the National Natural Science Foundation of China(32060349)China Scholarship Council([2021]15)。
文摘Studying the dynamics of plant populations is crucial to the conservation and management of endangered plants.The diameter at breast height(DBH),tree height,crown width,and environmental factors of a total of 15 plots in five populations in Guizhou Province,China were measured in this study.The method of substituting diameter at breast height for age was used to divide the population into 7 age classes.The age structure,static life table,and relationship between the population characteristics and environmental factors of the Litsea coreana Levl.var.sinensis population were studied.Moreover,the time series model was used to predict the population dynamics.Results showed that the age structure of population in Zhengan County(Population ZA)had an inverted Jshape with abundant seedlings and insufficient middle-aged and elderly individuals.The age structures of populations in Daozhen County(Population DZ),Kaiyang County(KY),Meitan County(Population MT),and Xishui County(Population XS)were spindle-shaped with few young individuals and many middle-aged and elderly individuals.The mortality rate of each population fluctuated with the increase in age class,and the populations were extremely unstable.The survival curve was close to the Deevey III type,and the degree of deviation was related to the lack of young individuals.After the age stages II,IV,and VI,the number of aged plants in the different populations initially increased then decreased,and population stability was difficult to maintain.Redundancy analysis showed that the DBH,tree height and crown width of the population decreased with the increase of annual mean temperature,and the population density was restricted by soil nutrient conditions to a certain extent.The results of this work provide scientific basis for the conservation and sustainable utilization of natural populations of L.coreana var.sinensis in Guizhou Province,China.
