忍冬木层孔菌对乳腺癌癌前病变大鼠的保护作用

目的:探讨忍冬木层孔菌醇提物对大鼠乳腺癌癌前病变的影响,为忍冬木层孔菌防治乳腺癌提供科学依据。方法:取雌性未孕SD大鼠,制备乳腺癌癌前病变模型。连续灌胃给药4周后观察大鼠一般情况、采用放射免疫法检测大鼠血清中性激素雌二醇(E2)、孕酮(P)、催乳素(PRL)、黄体生成素(LH)和卵泡刺激素(FSH)含量,用HE染色分析乳腺组织病理变化,用免疫组化分析乳腺组织中雌激素受体α(ERα)、β(ERβ)和孕激素受体(PR)蛋白表达变化。结果:忍冬木层孔菌醇提物600mg/kg能降低血清中E2水平(P<0.05),升高P、PRL的含量(P<0.05或P<0.01),对LH和FSH未见明显的影响;150、300、600mg/kg能降低卵巢、子宫质量指数(P<0.05或P<0.01),改善乳腺组织病理变化(P<0.05或P<0.01);600mg/kg逆转乳腺组织中上调的ERα、ERβ和PR的异常表达(P<0.05或P<0.01)。结论:忍冬木层孔菌醇提物能够调节乳腺癌癌前病变大鼠体内性激素水平和效应,抑制激素异常对乳腺组织的不良刺激,从而改善大鼠乳腺组织病理变化,有效的阻止乳腺癌癌前病变的发生、发展。

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常听到一些到机关办事的人有这样的感慨:“人难找、脸难看、事难办”,这种说法虽是老生常谈,但颇有针对性。且不论“人难找、事难办”,一个“脸难看”就够你受的了。对于难看的脸色,农村人用“好象欠他二百吊”的俗语来形容。

Variability Modes of the Winter Upper-Level Wind Field over Asian MidHigh Latitude Region

In this study,the NCEP/NCAR reanalysis dataset was used to analyze the variability modes of the winter upper-level wind field over Asian mid-high latitude region.As shown by the results,the dominant variability modes of the winter upper-level wind field over Asian mid-high latitude region are characterized by the out-of-phase variation in the intensity of the subtropical and temperate jets over East Asia and the meridional shift of the subtropical jet axis,on interannual and multiannual scales,respectively.The first leading variability mode can be used as a good measure to represent the integral variation of atmospheric general circulation in Asian mid-latitude region.Composite analyses suggest that the first leading variability mode of the winter upper-level wind field is intimately related to the atmospheric circulation and temperature anomalies in the northern hemispheric mid-latitude region.

The exceptionally strong and persistent Arctic stratospheric polar vortex in the winter of 2019–2020

The Arctic stratospheric polar vortex was exceptional strong,cold and persistent in the winter and spring of 2019–2020.Based on reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research and ozone observations from the Ozone Monitoring Instrument,the authors investigated the dynamical variation of the stratospheric polar vortex during winter 2019–2020 and its influence on surface weather and ozone depletion.This strong stratospheric polar vortex was affected by the less active upward propagation of planetary waves.The seasonal transition of the stratosphere during the stratospheric final warming event in spring 2020 occurred late due to the persistence of the polar vortex.A positive Northern Annular Mode index propagated from the stratosphere to the surface,where it was consistent with the Arctic Oscillation and North Atlantic Oscillation indices.As a result,the surface temperature in Eurasia and North America was generally warmer than the climatology.In some places of Eurasia,the surface temperature was about 10 K warmer during the period from January to February 2020.The most serious Arctic ozone depletion since 2004 has been observed since February 2020.The mean total column ozone within 60°–90°N from March to 15 April was about 80 DU less than the climatology.

Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature

Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar region.After the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate periods.Period I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating downwards.In Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the troposphere.The anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over Eurasia.The zero line between negative and positive temperature anomalies moves southwards during days 5-20.Stratospheric cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole structure.During PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the troposphere.Specifically,a wave train is initiated from the North Atlantic region to northern Europe.The propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central Asia.Therefore,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period.

Long-term temperature variation of the Southern Yellow Sea Cold Water Mass from 1976 to 2006

This paper discusses the long-term temperature variation of the Southern Yellow Sea Cold Water Mass(SYSCWM)and examines those factors that infl uence the SYSCWM,based on hydrographic datasets of the China National Standard Section and the Korea Oceanographic Data Center.Surface air temperature,meridional wind speed,and sea surface temperature data are used to describe the seasonal changes.Mean temperature of the two centers of the SYSCWM had diff erent long-term trends.The temperature of the center in the west of the SYSCWM was rising whereas that of the center in the east was falling.Mean temperature of the western center was related to warm water intrusion of the Yellow Sea Warm Current,the winter meridional wind,and the winter air temperature.Summer process played a primary role in the cooling trend of temperature in the eastern center.A decreasing trend of salinity in the eastern half of the SYSCWM showed that warm water intrusion from the south might weaken,as could the SYSCWM circulation.Weakened circulation provided less horizontal heat input to the eastern half of the SYSCWM.Less lateral heat input may have led to the decreasing trend in temperature of the eastern center of the SYSCWM.Further,warmer sea surface temperatures and less heat input in the deep layers intensifi ed the thermocline of the eastern SYSCWM.A stronger thermocline had less heat fl ux input from upper layers to this half of the SYSCWM.Stronger thermocline and weakened heat input can be seen as two main causes of the cooling temperature trend of the eastern center of the SYSCWM.

Decadal changes of the wintertime tropical tropospheric temperature and their influences on the extratropical climate

A decadal change of the tropical tropospheric temperature （TT） was identified to occur in the winter of 1997. Compared with that in the former period （1979-1996）, the wintertime TT was significantly high over most of the tropical regions except over the tropical eastern Pacific during the latter period （1997-2014） because the sea surface temperature （SST） exhibited a decadal La Nifia-like pattern after 1997. The warm SST anomalies over the tropical western Pacific facilitated enhanced precipitation and increased heat release to the tropical atmosphere, leading to a warmer tropical tropo- sphere in the latter period. In addition to the mean TT values, the interannual variability of the tropical TT changed in 1997. The leading mode of the tropical TT explained 72.9 % of the total variance in the former period. It led to significant warming over midlatitude North America via a Pacific-North America （PNA）-like wave train and off the coast of East Asia via an anomalous lower-tropospheric anticyclone around the Philippines. The mode remained a similar pattern but explained 85.4 % of the total variance in the latter period, and its location was slightly westward-shifted compared with that in the former period. As a result, the structure of the PNA-like wave train changed, leading to anomalous warming over northwestern North America and enhanced precipitation over the southern North America. Meanwhile, the anomalous lower- tropospheric anticyclone around the Philippines shifted westward, leading to increased precipitation and regional warming over East Asia. The decadal changes of the leading mode of the tropical TT and its influences on the extratropical climate can be attributed to the changes of the tropical SST variability.

Seasonal timing of stratospheric final warming associated with the intensity of stratospheric sudden warming in preceding winter

The association of seasonal timing of stratospheric final warming events(SFWs) in spring and the occurrence of major and minor stratospheric sudden warming events(SSWs) in midwinter were investigated through statistical analysis, parallel comparison, and composite analysis, based on the NCEP-NCAR reanalysis dataset covering 1958–2012. It was found that the intensity and occurrence of winter SSW events can largely affect the timing of spring SFWs. Specifically, the SFW onset dates tend to be later(earlier) after the occurrence(absence) of winter major SSWs. However, the occurrence or absence of minor SSWs does not change the frequency of early and late SFWs. A parallel comparison of the temporal evolution of the anomalous circulation and planetary-waves between major SSW and minor SSW winters indicates that the stratospheric polar vortex(polar jet) will keep being anomalously stronger 30 days after major SSW onset. And the associated significant negative Eliassen-Palm(EP) flux anomalies can persist for as long as 45 days after major SSW events. In contrast, the circulation anomalies around the occurrence of minor SSW events can last only a few days. To further verify the possible influence of the occurrence of major SSWs on the seasonal timing of SFWs, composite analysis was performed respectively for the 21 major-SSW years, 15 minor-SSW years, and the 15 non-SSW years. Generally, planetary-wave activity in the extratropical stratosphere tends to be stronger(weaker) and the westerly polar jet is anomalously weaker(stronger) in major-SSW(non-SSW) winters. But in the following spring, the planetary-wave activity is weaker(stronger) accompanied with an anomalously stronger(weaker) stratospheric polar vortex. In spring after minor-SSW years, however, the stratospheric polar vortex and the westerly polar jet exhibit a state close to climatology with relatively gentle variations.