The ring-width chronology of a Juniperus przewalskii tree from the middle of the Qilian Mountain was constructed to estimate the annual precipitation (from previous August to current July) since AD 1480.The reconstruc...The ring-width chronology of a Juniperus przewalskii tree from the middle of the Qilian Mountain was constructed to estimate the annual precipitation (from previous August to current July) since AD 1480.The reconstruction showed four major alternations of drying and wetting over the past 521 years.The rainy 16th century was followed by persistent drought in the 17th century.Moreover,relatively wet conditions persisted from the 18th to the beginning of 20th century until the recurrence of a drought during the 1920s and 1930s.Based on the Empirical Mode Decomposition method,eight Intrinsic Mode Functions (IMFs) were extracted,each representing unique fluctuations of the reconstructed precipitation in the time-frequency domain.The high amplitudes of IMFs on different timescales were often consistent with the high amount of precipitation,and vice versa.The IMF of the lowest frequency indicated that the precipitation has undergone a slow increasing trend over the past 521 years.The 2-3 year and 5-8 year time-scales reflected the characteristics of inter-annual variability in precipitation relevant to regional atmospheric circulation and the El Ni?o-Southern Oscillation (ENSO),respectively.The 10-13 year scale of IMF may be associated with changing solar activity.Specifically,an amalgamation of previous and present data showed that droughts were likely to be a historically persistent feature of the Earth's climate,whereas the probability of intensified rainfall events seemed to increase during the course of the 19th and 20th centuries.These changing characteristics in precipitation indicate an unprecedented alteration of the hydrological cycle,with unknown future amplitude.Our reconstruction complements existing information on past precipitation changes in the Qilian Mountain,and provides additional low-frequency information not previously available.展开更多
文摘目的观察小剂量托珠单抗联合糖皮质激素(简称激素)治疗极晚发型重症肌无力(very-late-onset myasthenia gravis,VLOMG)患者的疗效及安全性。方法收集2020年9月至2021年9月作者单位收治的VLOMG患者6例,其中男2例、女4例,平均年龄(74.1±4.5)岁,病程0.5~38个月,中位数13个月。给予患者甲基泼尼松龙冲击联合托珠单抗治疗,托珠单抗治疗方案为按体重4 mg/kg静脉注射,每隔4周1次,连续3次。于治疗前及治疗后1、2、3个月对患者进行美国重症肌无力协会(Myasthenia Gravis Foundation of America,MGFA)定量评分(quantitative myasthenia gravis scale,QMGS)、重症肌无力日常活动评分(myasthenia gravis-activity of daily living,MG-ADL),同时检测患者血常规、肝肾功能情况,并记录患者不良反应。结果与治疗前比较,治疗3个月时患者QMGS评分和MG-ADL评分均降低[(4.5±2.5)分比(13.8±5.5)分,t=4.33,P=0.007;(1.3±1.4)分比(8.0±4.4)分,t=4.10,P=0.009]。治疗过程中除1例患者因皮肤感染延迟用药1个月外,其他患者未诉特殊不适。结论小剂量托珠单抗联合激素治疗VLOMG可显著缓解MG症状,且无明显的不良反应,提示托珠单抗可能在治疗VLOMG中具有治疗潜能,但其确切疗效及安全性尚需进一步证实。
基金supported by the National Natural Science Foundation of China (Grant Nos. 41001058, 41001009, 40971119 and 40890052)the China Postdoctoral Science Foundation (Grant Nos. 201003194)
文摘The ring-width chronology of a Juniperus przewalskii tree from the middle of the Qilian Mountain was constructed to estimate the annual precipitation (from previous August to current July) since AD 1480.The reconstruction showed four major alternations of drying and wetting over the past 521 years.The rainy 16th century was followed by persistent drought in the 17th century.Moreover,relatively wet conditions persisted from the 18th to the beginning of 20th century until the recurrence of a drought during the 1920s and 1930s.Based on the Empirical Mode Decomposition method,eight Intrinsic Mode Functions (IMFs) were extracted,each representing unique fluctuations of the reconstructed precipitation in the time-frequency domain.The high amplitudes of IMFs on different timescales were often consistent with the high amount of precipitation,and vice versa.The IMF of the lowest frequency indicated that the precipitation has undergone a slow increasing trend over the past 521 years.The 2-3 year and 5-8 year time-scales reflected the characteristics of inter-annual variability in precipitation relevant to regional atmospheric circulation and the El Ni?o-Southern Oscillation (ENSO),respectively.The 10-13 year scale of IMF may be associated with changing solar activity.Specifically,an amalgamation of previous and present data showed that droughts were likely to be a historically persistent feature of the Earth's climate,whereas the probability of intensified rainfall events seemed to increase during the course of the 19th and 20th centuries.These changing characteristics in precipitation indicate an unprecedented alteration of the hydrological cycle,with unknown future amplitude.Our reconstruction complements existing information on past precipitation changes in the Qilian Mountain,and provides additional low-frequency information not previously available.
