This paper is devoted to establishing a critical value of the concentration of one intermediary reactant which determines whether pattern solutions of a class of Brusselator models exist or not.We introduce a new meth...This paper is devoted to establishing a critical value of the concentration of one intermediary reactant which determines whether pattern solutions of a class of Brusselator models exist or not.We introduce a new method to compute the degree index of the related linear operator so that the obtained sufficient conditions are easier to verify than those in the known references.The proofs mainly rely on Leray-Schauder degree theory,implicit function theorem and analytical techniques.展开更多
Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality...Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality over age group are linear, this is not the feature of mortality model. To avoid this disadvantage, O-U type processes will be used to model the log-mortality in this paper. In fact, this model is an AR(1) process, but with a nonlinear time drift term.Based on the mortality data of America from Human Mortality database(HMD), mortality projection consistently indicates a preference for mortality with O-U type processes over those with the classical Lee-Carter model. By means of this model, the low bounds of mortality rates at every age are given. Therefore, lengthening of maximum life expectancies span is estimated in this paper.展开更多
文摘目的探讨酶法提取大鲵(Andrias davidianus)皮胶原蛋白肽的抗原性,为进一步研究大鲵皮胶原蛋白肽的生物相容性提供依据。方法采用酶法提取获得大鲵皮胶原蛋白肽,并对得到的胶原蛋白肽进行基质辅助激光解吸电离飞行时间质谱法(matrix assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF-MS)分析,确定其分子量分布范围。将得到的胶原蛋白肽与弗氏佐剂混合乳化后经免疫程序免疫ICR(Institute of Cancer Research)小鼠,采用抗体酶联免疫试剂盒检测小鼠血清中IgG、IgA、IgM及IgE含量。结果酶解后的胶原蛋白肽分子量均小于10 k Da,多数肽分子量集中在2000~5000 m/z,检测血清中Ig A、Ig G、Ig M和Ig E 4种免疫球蛋白的质量浓度范围分别是71.63~85.90μg/m L、705.19~857.04 ng/m L、47.04~57.46 ng/m L与224.54~261.0μg/m L。结论采用碱性蛋白酶酶解获得的大鲵皮胶原蛋白肽对ICR小鼠呈现出较弱的抗原性。
基金supported by the National Natural Science Foundation of China(No.11671359)the Science Foundation of Zhejiang Sci-Tech University under Grant No.15062173-Ysupported by the provincial Natural Science Foundation of Zhejiang(LY16A010009)
文摘This paper is devoted to establishing a critical value of the concentration of one intermediary reactant which determines whether pattern solutions of a class of Brusselator models exist or not.We introduce a new method to compute the degree index of the related linear operator so that the obtained sufficient conditions are easier to verify than those in the known references.The proofs mainly rely on Leray-Schauder degree theory,implicit function theorem and analytical techniques.
基金Supported by National Social Science Fund of China(17BTJ023)
文摘Modeling log-mortality rates on O-U type processes and forecasting life expectancies are explored using U.S. data. In the classic Lee-Carter model of mortality, the time trend and the age-specific pattern of mortality over age group are linear, this is not the feature of mortality model. To avoid this disadvantage, O-U type processes will be used to model the log-mortality in this paper. In fact, this model is an AR(1) process, but with a nonlinear time drift term.Based on the mortality data of America from Human Mortality database(HMD), mortality projection consistently indicates a preference for mortality with O-U type processes over those with the classical Lee-Carter model. By means of this model, the low bounds of mortality rates at every age are given. Therefore, lengthening of maximum life expectancies span is estimated in this paper.
