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A climatic reversal.at the last interglacial-last glacial transition recorded in the loess section at Zhaitang, Beijing

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Chinese Science Bulletin 1999年第6期44卷 571-575页

作者： Shangfa Xiong Dongsheng Liu Zhongli Ding Chinese Acad Sci Inst Geol Beijing 100029 Peoples R China

A weakly developed paleosol was identified at S1-L1 transition of the loess section of Zhaitang, Beijing. This paleosol may represent a climatic reversal.which is associated with the strengthening in summer monsoon and correlated well with the climatic regression event documented in the paleoclimate records from Greenland ice, marine sediments and European pollen at the last interglacial-last glacial transition.

关键词： last interglacial period last glacial period loess paleosol climatic reversal.

Dramatic variations in the Earth's main magnetic field during the 20th century

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Chinese Science Bulletin 2000年第21期45卷 2013-2016页

作者： Wenyao Xu Zigang Wei Shizhuang Ma Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

Analysis of the International Geomagnetic Reference Field (IGRF) 1900-2000 showsthat the Earth’s main magnetic field has changed dramatically during the 20th century: its dipole moment has decreased by 6.5% since 1900, the strengths of its quadrupole and octupole have increased by 95% and 74%, respectively, four major planetary-scale magnetic anomalies on the Earth’s surface have enhanced by 21%-56%, and the magnetic center has shifted 200 km towards the Pacific Ocean. These time-variation features are similar to the behavior before a geomagnetic polarity reversal.

关键词： Earth’s main magnetic field secular variation geomagnetic polarity reversal.

In Vitro Study of Ultrasound on Multidrug Resistance in MDR Human Hepatoma HepG_2 Cells

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Chinese Journal of Clinical Oncology 2008年第3期5卷 165-171页

作者： Qiujun Qi Baojin Zhai Yumian Guo Zhihong Wang Feng Wu The Traditional Chinese Medical Hospital of Tianjin Hedong District Tianjin 300162 China. Department of Neurological Surgery The Affiliated Hospital of The Medical College of Chinese People＇s Armed Police Force Tianjin 300162 China. Institute of Ultrasound and Engineering in Medicine Chongqing University of Medical Science Chongqing 400016 China.

OBJECTIVE The aim of the study was to examine the reversal.effects of ultrasound （US） on the MDR in HepG2/ADM, a HepG2 cell line resistant to Adriamycin （ADM）, and to study the mechanism of US action.METHODS Using the MTT assay, the effects of US on MDR in HepG2/ADR cells were studied. Before and after the treatment with 0.5 W/cm^2 low intensity ultrasound （LIUS）, the expression of the MDR-related genes, mdrl, mrp and lrp was assayed with the reverse transcriptase polymerase chain reaction （RT-PCR） and the levels of their respective protein expression determined by flow cytometry. By using confocal laser scanning microscopy （CLSM）, we examined the intracellular daunorubicin （DNR） distribution, and the effects on the cells of treatment with US or DNR.RESULTS LIUS significantly reversed MDR in HepG2/ADR cells. After treatment with LIUS at 0.5 W/cm^2, chemosensitivity to ADM and DNR increased 3.35-fold and 2.81-fold, respectively. The reversal.activity by LIUS plus verapamil （VER） was stronger than with either US or VER alone. After treatment with 0.5 W/cm^2, the expression of both the MDR1 and the MRP mRNA genes began to decline （P 〈 0.01 and P 〈 0.05, respectively）; the expression of LRP showed no significant changes. Changes in the expression of the P-glycoprotein （P-gp） and MRP were similar to those of their mRNA expressions. Results of the CLSM showed that administration of US （0. 5 W/cm^2） or VER （15.7 uM） with DNR to HepGa/ADM cells showed a significant change in the distribution of DNR in the cells.CONCLUSION Our results show that LIUS can reverse MDR. The reversal.effects are stronger than those of either US or VER alone, when combined with VER administration. As LIUS is noninvasive causing no toxicity, it might have potential for clinical application. The reversal.mechanism needs further study.

关键词： multidrug resistance (MDR) HepG2/ADM ultra-sound (US) reversal.