Urbanization,especially urban land expansion,has a profound influence on the urban thermal environment.Cities in Northeast China face remarkably uneven development and environmental issues,and thus it is necessary to ...Urbanization,especially urban land expansion,has a profound influence on the urban thermal environment.Cities in Northeast China face remarkably uneven development and environmental issues,and thus it is necessary to strengthen the diagnosis of thermal environmental pressure brought by urbanization.In this study,multi remote sensing imageries and statistical approaches,involving piecewise linear regression(PLR),were used to explore urban expansion and its effects on the thermal environment of Changchun City in Jilin Province,China.Results show that Changchun experienced rapid urban expansion from 2000 to 2020,with urban built-up areas increasing from 171.77 to 525.14 km^(2).The area of the city’s urban heat island(UHI)increased dramatically,during both day and night.Using PLR,a positive linear correlation of built-up density with land surface temperature(LST)was detected,with critical breakpoints of 70%-80%during the daytime and 40%-50%at nighttime.Above the thresholds,the magnitude of LST in response to built-up density significantly increased with intensifying urbanization,especially for nighttime LST.An analysis of the relative frequency distributions(RFDs)of LST reveals that rapid urbanization resulted in a significant increase of mean LST in newly urbanized areas,but had weak effects on daytime LST change in existing urban area.Urban expansion also contributed to a constant decrease of spatial heterogeneity of LST in existing urban area,especially at daytime.However,in newly urbanized areas,the spatial heterogeneity of LST was decreased during the daytime but increased at nighttime due to urbanization.展开更多
[目的]探讨二肽基肽酶4抑制剂(DPP-4i)对2型糖尿病(T2DM)患者血清肌酐(Cr)的影响。[方法]系统检索PubMed、Embase、Cochrane Library和Web of Science数据库,纳入DPP-4i治疗T2DM患者调节Cr的随机对照试验(RCT)。采用固定效应或随机效应...[目的]探讨二肽基肽酶4抑制剂(DPP-4i)对2型糖尿病(T2DM)患者血清肌酐(Cr)的影响。[方法]系统检索PubMed、Embase、Cochrane Library和Web of Science数据库,纳入DPP-4i治疗T2DM患者调节Cr的随机对照试验(RCT)。采用固定效应或随机效应模型进行数据拟合,采用I^(2)指数定量评价异质性,使用标准方法进行敏感性分析和发表偏倚检验。[结果]经系统检索数据库,纳入12项RCT,共计2276名受试者。由于潜在异质性的原因,故采用随机效应模型进行数据拟合,DPP-4i治疗可轻度提高T2DM患者的Cr水平(WMD:0.15 mg/L,95%CI:0.03~0.27,I^(2)=18%,P=0.02),结果具有统计学差异。根据敏感性测试,Meta分析其结果较为可靠。同时进行Begg’s与Egger’s检验,未见发表偏倚。[结论]T2DM患者应用DPP-4i进行降糖治疗,可能会出现血Cr水平轻度升高。未来还需开展更大样本量的多中心研究,以进一步探讨DPP-4i治疗引起Cr水平改变的临床意义。展开更多
基金Under the auspices of the Natural Science Foundation of Jilin Province(No.20200201048JC)。
文摘Urbanization,especially urban land expansion,has a profound influence on the urban thermal environment.Cities in Northeast China face remarkably uneven development and environmental issues,and thus it is necessary to strengthen the diagnosis of thermal environmental pressure brought by urbanization.In this study,multi remote sensing imageries and statistical approaches,involving piecewise linear regression(PLR),were used to explore urban expansion and its effects on the thermal environment of Changchun City in Jilin Province,China.Results show that Changchun experienced rapid urban expansion from 2000 to 2020,with urban built-up areas increasing from 171.77 to 525.14 km^(2).The area of the city’s urban heat island(UHI)increased dramatically,during both day and night.Using PLR,a positive linear correlation of built-up density with land surface temperature(LST)was detected,with critical breakpoints of 70%-80%during the daytime and 40%-50%at nighttime.Above the thresholds,the magnitude of LST in response to built-up density significantly increased with intensifying urbanization,especially for nighttime LST.An analysis of the relative frequency distributions(RFDs)of LST reveals that rapid urbanization resulted in a significant increase of mean LST in newly urbanized areas,but had weak effects on daytime LST change in existing urban area.Urban expansion also contributed to a constant decrease of spatial heterogeneity of LST in existing urban area,especially at daytime.However,in newly urbanized areas,the spatial heterogeneity of LST was decreased during the daytime but increased at nighttime due to urbanization.
文摘[目的]探讨二肽基肽酶4抑制剂(DPP-4i)对2型糖尿病(T2DM)患者血清肌酐(Cr)的影响。[方法]系统检索PubMed、Embase、Cochrane Library和Web of Science数据库,纳入DPP-4i治疗T2DM患者调节Cr的随机对照试验(RCT)。采用固定效应或随机效应模型进行数据拟合,采用I^(2)指数定量评价异质性,使用标准方法进行敏感性分析和发表偏倚检验。[结果]经系统检索数据库,纳入12项RCT,共计2276名受试者。由于潜在异质性的原因,故采用随机效应模型进行数据拟合,DPP-4i治疗可轻度提高T2DM患者的Cr水平(WMD:0.15 mg/L,95%CI:0.03~0.27,I^(2)=18%,P=0.02),结果具有统计学差异。根据敏感性测试,Meta分析其结果较为可靠。同时进行Begg’s与Egger’s检验,未见发表偏倚。[结论]T2DM患者应用DPP-4i进行降糖治疗,可能会出现血Cr水平轻度升高。未来还需开展更大样本量的多中心研究,以进一步探讨DPP-4i治疗引起Cr水平改变的临床意义。
