Economics literature has long overlooked an important economic phenomenon:Residents in large cities tend to save a smaller percentage of their disposable income than their peers in small and medium-sized cities.As an ...Economics literature has long overlooked an important economic phenomenon:Residents in large cities tend to save a smaller percentage of their disposable income than their peers in small and medium-sized cities.As an explanation for this phenomenon,this paper puts forth the hypothesis that:Residents in large cities purchase more services to increase their leisure time,which is reduced by longer commuting time than in small and medium-sized cities,thus lowering their household savings rate.We conducted an empirical study using panel data of China’s prefecture-level cities and urban household survey data,and employed an instrumental variable to address the endogeneity problem.The result confirmed the accuracy of the above hypothesis.In identifying the economic phenomenon and putting forth the hypothesis,this paper(i)creates a theoretical link between city size and household savings rate,which helps unravel the determinants of the urban household savings rate;(2)provides important implications for China’s policy-making on domestic consumption,urban populations,and industrial development.Priority should be given to developing large and medium-sized cities given the positive effects on domestic consumption and service sector development,and migrant labor shall not be barred from entering large and medium-sized cities to provide services to local residents.展开更多
目的观察脂联素(adiponectin,APN)通过蛋白质激酶C(protein kinase C,PKC)/活化蛋白激酶C受体1(receptor for activated C kinase 1,RACK1)途径对血管平滑肌细胞(vascular smooth muscle cells,VSMCs)泡沫化过程的影响,并探讨其可能机制...目的观察脂联素(adiponectin,APN)通过蛋白质激酶C(protein kinase C,PKC)/活化蛋白激酶C受体1(receptor for activated C kinase 1,RACK1)途径对血管平滑肌细胞(vascular smooth muscle cells,VSMCs)泡沫化过程的影响,并探讨其可能机制.方法体外培养VSMCs,并分为空白对照组、氧化型低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)组和ox-LDL+APN组,其中空白对照组细胞正常培养,其余两组均采用ox-LDL(50μg/mL)刺激细胞建立泡沫化模型.APN给药完成后,油红O染色和胆固醇含量测定分析细胞泡沫化情况,Western-blot和逆转录-PCR分别检测细胞PKC、RACK1蛋白和基因的表达情况.结果与空白对照组比较,ox-LDL模型组细胞的细胞核突出,胞质内聚集大量红色脂滴,呈泡沫样改变,细胞胆固醇水平由(21.34±4.35)μmol/L升高至(109.97±11.60)μmol/L,差异有统计学意义(t=41.27,P<0.05),PKC、RACK1蛋白和基因表达均显著上升(t值分别为11.64、14.58和27.90、24.38,P值均<0.05);在给予APN干预后,细胞内红色脂滴散去,泡沫细胞数量明显减少,胆固醇含量下降为(54.27±6.89)μmol/L(P<0.05),PKC、RACK1蛋白和基因表达均明显得到抑制(t值分别为7.57、8.91和13.27、10.99,P值均<0.05).结论 APN能明显抑制VSMCs泡沫化,其作用机制可能与调控PKC/RACK1途径有关.展开更多
基金This paper is a result of the major program of the Key Research Base for Humanities and Social Sciences of the Ministry of Education“Structural Transition,Urban Development and China’s Economic Growth”(Grant No.17JJD790005)sponsorships from the National Natural Science Foundation of China(NSFC)(Grant No.71841008,71833003,71863001)the Peak Program for Theoretical Economics at Fudan University。
文摘Economics literature has long overlooked an important economic phenomenon:Residents in large cities tend to save a smaller percentage of their disposable income than their peers in small and medium-sized cities.As an explanation for this phenomenon,this paper puts forth the hypothesis that:Residents in large cities purchase more services to increase their leisure time,which is reduced by longer commuting time than in small and medium-sized cities,thus lowering their household savings rate.We conducted an empirical study using panel data of China’s prefecture-level cities and urban household survey data,and employed an instrumental variable to address the endogeneity problem.The result confirmed the accuracy of the above hypothesis.In identifying the economic phenomenon and putting forth the hypothesis,this paper(i)creates a theoretical link between city size and household savings rate,which helps unravel the determinants of the urban household savings rate;(2)provides important implications for China’s policy-making on domestic consumption,urban populations,and industrial development.Priority should be given to developing large and medium-sized cities given the positive effects on domestic consumption and service sector development,and migrant labor shall not be barred from entering large and medium-sized cities to provide services to local residents.
文摘目的观察脂联素(adiponectin,APN)通过蛋白质激酶C(protein kinase C,PKC)/活化蛋白激酶C受体1(receptor for activated C kinase 1,RACK1)途径对血管平滑肌细胞(vascular smooth muscle cells,VSMCs)泡沫化过程的影响,并探讨其可能机制.方法体外培养VSMCs,并分为空白对照组、氧化型低密度脂蛋白(oxidized low density lipoprotein,ox-LDL)组和ox-LDL+APN组,其中空白对照组细胞正常培养,其余两组均采用ox-LDL(50μg/mL)刺激细胞建立泡沫化模型.APN给药完成后,油红O染色和胆固醇含量测定分析细胞泡沫化情况,Western-blot和逆转录-PCR分别检测细胞PKC、RACK1蛋白和基因的表达情况.结果与空白对照组比较,ox-LDL模型组细胞的细胞核突出,胞质内聚集大量红色脂滴,呈泡沫样改变,细胞胆固醇水平由(21.34±4.35)μmol/L升高至(109.97±11.60)μmol/L,差异有统计学意义(t=41.27,P<0.05),PKC、RACK1蛋白和基因表达均显著上升(t值分别为11.64、14.58和27.90、24.38,P值均<0.05);在给予APN干预后,细胞内红色脂滴散去,泡沫细胞数量明显减少,胆固醇含量下降为(54.27±6.89)μmol/L(P<0.05),PKC、RACK1蛋白和基因表达均明显得到抑制(t值分别为7.57、8.91和13.27、10.99,P值均<0.05).结论 APN能明显抑制VSMCs泡沫化,其作用机制可能与调控PKC/RACK1途径有关.
