The evolution and present status of the study on peak oil in China

Peak oil theory is a theory concerning long-term oil reserves and the rate of oil production. Peak oil refers to the maximum rate of the production of oil or gas in any area under consideration. Its inevitability is analyzed from three aspects. The factors that influence peak oil and their mechanisms are discussed. These include the amount of resources, the discovery maturity of resources, the depletion rate of reserves and the demand for oil. The advance in the study of peak oil in China is divided into three stages. The main characteristics, main researchers, forecast results and research methods are described in each stage. The progress of the study of peak oil in China is summarized and the present problems are analyzed. Finally three development trends of peak oil study in China are presented.

非痴呆型血管性认知障碍患者海马表观扩散系数平均值研究

目的探讨非痴呆型血管性认知障碍(VCIND)患者两侧海马表观扩散系数平均值(ADC_(mean))与认知功能的关系。方法对43例VCIND患者(VCIND组)和43名条件匹配的志愿者(NC组)行常规头颅MRI检查,测量两侧海马体积,以两侧海马作为感兴趣区(ROI),检测其ADC_(mean)值并进行分析,将VCIND组和NC组的ADC_(mean)值与蒙特利尔认知评估量表(MoCA)评分进行相关分析。所有实验对象均为右利手。结果VCIND组和NC组组内和组间海马体积比较无明显差异(P>0.05)。VCIND组两侧海马ADC_(mean)值均较NC组增高,差异有统计学意义(t=5.36,P<0.05;t=4.84,P<0.05)。VCIND组和NC组左侧海马ADC_(mean)值均高于对侧,差异有统计学意义(t=6.16,P<0.05;t=5.29,P<0.05)。VCIND组两侧海马ADC_(mean)值均与MoCA评分具有明显相关性(rs=-0.84,P<0.05;rs=-0.74,P<0.05)。结论在海马发生形态学改变之前,ADC_(mean)值可以从分子影像学角度准确、快速地反映VCIND患者海马水分子的扩散能力,ADC_(mean)值的升高提示海马存在微观结构的损伤,一定程度上可以反映VCIND患者认知功能的改变,可能是该病早期诊断的可靠的分子影像学依据。