寒武纪生物爆发前的死劫难海洋

白垩纪/第三纪界线研究揭示,界线事件留下铱异常和碳同位素异常信息(Alvarez,1980;Hsü et al., 1982)。近来,二叠纪/三叠纪界线粘土中也发现了Ir-δ¹³C双异常(SunYiyin et al.,1984)。     

ECONOMIC-LOGIC, CONCEPTS AND METHODS: ANALYTICAL AIDS IN SEDIMENT MANAGEMENT

I. INTRODUCTION AND PERSPECTIVEIn planning, implementing and monitoring water and related resources developmentS, the effectsof erosion and sedimentation on man,s economic activities, his health and welfare and on the environment, have to be taken into ac…     

尼泊尔喜马拉雅地区地震活动的季节性调制变化

1995～2000年期间,尼泊尔地震台网记录到的夏季地震次数比冬季地震次数少37±8%;其中ML>2级的地震少31%,而ML>4级的地震少63%。我们的研究表明,观测到这种现象是偶然的概率小于1%。我们发现,其原因或者是大多数地表面加载太小,或者这些加载的反极性效应使得冬季的地震活动性增强。我们认为,孕震深度孔隙压力增大导致的库仑破裂是一种可能的机制。然而,这样一种机制需要流体扩散比地表面加载滞后6个月,这种机制是可能的,尽管可能性很小。我们更倾向于这样一种解释:恒河和印度北部伴随季风降雨的应力加载使夏季地震活动受到抑制,其机制将在另一篇论文中讨论。     

Antiproliferative and apoptosis-inducing potential of 3β-hydroxy-△5-steroidal congeners purified from the soft coral Dendronephthya putteri

The exploration and identification of antiproliferative phytochemicals have received increased attention in medicinal chemistry. In particular, research focused on the toxicology of marine natural products has increased in recent years. Terpenoids, among many secondary metabolites, have been demonstrated to act as effective anticancer agents. Soft corals, a group of marine invertebrates, produce a variety of terpenoids with biofunctional properties. The current study presents the extraction, purification, and identification of sterol congeners from the soft coral Dendronephthya putteri. The method involves 50% chloroform-methanol extraction, polar column fractionation, and analysis through GC-MSn. Dose-dependent antiproliferative activity was observed within the sterol-rich fraction (DPCMH 2-4), which consisted of 3β-hydroxy-Δ5-steroidal congeners. This fraction inhibited the growth of HL-60 and MCF-7 cells with IC50 values of 25.27±1.43 and 22.81±0.15 μg/mL, respectively. Apoptotic body formation, DNA damage, cell cycle arrest, and apoptotic cell signaling pathway activation were also observed, reinforcing the dose-dependent antiproliferative and apoptosis-inducing activity of 3β-hydroxy-Δ5-steroidal congeners. To our knowledge, this is the first report of anticancer agent identification from the soft coral D. putteri. Based on the observations, these steroidal congeners are promising candidates for the development of anticancer drugs.     

Probable satellite thermal infrared anomaly before the Zhangbei M s=6.2 earthquake on January 10, 1998

This paper used the thermal infrared data of the satellite NOAA-AAVHRR of the north part of North China (113°～119° E, 38°～42° N), and processed the remote sensing data through radiation adjustment, geometric adjustment and so on by the software ＂The Monitoring and Fast Process System of Earthquake Precursor Thermal Infrared Anomaly＂, inversed the earth surface temperature. Some disturbances effect had been excluded, and thermal infrared temperature anomaly had been extracted by the picture difference method. The Zhangbei MS=6.2 earthquake is used as the example in the paper, so that in the paper thermal infrared characteristics on time-space before earthquake and the relationship between the anomaly and the earthquake prediction have been summarized.Within more than ten days before the Zhangbei earthquake, the thermal infrared anomaly had emerged widely along Zhangjiakou-Bohai seismic belt, and the anomalous region seemed like a belt and it is also consistent with the tectonic background there; the anomaly expanded from the outside toward the earthquake focus, but the focus lay at the edge of the thermal infrared region. So it is possible to explore a new anomaly observation method for earthquake prediction by observing and studying the satellite thermal infrared anomaly before big earthquakes happen.     

大型电力工程场地地震危险性研究现状与展望

概述了工程场地地震危险性分析的研究简史、内容和方法,并就研究工作中存在的问题和发展趋势进行了讨论.提出了利用GIS技术研制我国大型电力工程地震危险性分析信息系统的建议.     

Effects of heavy metals （Pb^2＋ and Cd^2＋） on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb²⁺ and Cd²⁺ (0, 0.5, 1, 2, 4, 6 and 8 mg/L). The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased (>4 mg/L Pb²⁺) metal concentration. The photosynthetic apparatus (thylakoid membranes) were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration (8 mg/L Pb²⁺), the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations (0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L Pb²⁺), both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents (chlorophyll α, β carotene and phycocyanin) were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb²⁺, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll α, β carotene and phycocyanin respectively over the control. Corresponding reductions for the same Cd²⁺concentrations were 57.83, 48.94 and 56.90%. Lethal concentration (96 h LC₅₀) values (3.47 mg/L Cd²⁺ and 12.11 mg/L Pb²⁺) indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd²⁺ than Pb²⁺. Supported by the Chinese Scholarship Council     

缅甸Kayan州Mawchi矿山锡—钨成矿作用的流体包裹体研究

Mawchi矿山位于缅甸Kayah州,北纬18°49′,东经97°10′,一般标高1.1Km(图1).在第二次世界大战前,Mawchi是世界上最大的锡和钨的产地之一.从1939到1940年,它生产了缅甸钨的总产量的60%,当时,缅甸的钨的总产量占世界钨的产量的17.4%.地质背景Mawchi矿区地质图见图2.这个地区以由砂岩、砂砾岩、钙质泥岩、页岩和灰岩组成的沉积岩系为特征;在矿区范围内被称为Mawchi系,它可以与Tennanserim的Tavoy地区内的Mergni系对比.一个小的花岗岩类侵入体侵位于Mawchi矿区的沉积岩中,并产生了一个低品位的热变质晕,由大理岩、石英岩、斑点砂砾岩和硬化板岩组成.Mawchi花岗岩类侵入体是Sn-W有关的.缅甸花岗岩带中最小的岩体之一.根据目前所获取的地层证据和K—Ar年代测定法(Garson等.1976:Mitehell,1977),这个带侵位的时代被认为是晚中     

中国大陆科学钻探主孔0-4000m岩心的裂变径迹年龄测定

对中国大陆科学钻探（CCSD）主孔0～4000的岩心样进行了裂变径迹年龄测定。在不同深度共测定了38个样品的磷灰石裂变径迹年龄，磷灰石的裂变径迹年龄数据分布在98．6-3．2Ma之间，年龄值的变化规律总体上是随钻孔深度的增加而逐渐减少，地表样的磷灰石裂变径迹年龄是87．1Ma，至3899m深处则为3．2Ma，基于磷灰石中裂变径迹的退火特征，反映出地壳温度随深度的增加而增加的规律。年龄值随深度的变化，也有若干波动，尤其是1550～2450m之间的这部分岩心，在年龄随深度变化的趋势上是不连续的，这部分岩体可以认为是一个重要的构造作用带。根据年龄一深度关系和约束径迹长度的分布特征，对超高压变质岩体的后期折返机制进行了探讨。     

美国金属矿床和经济地质研究的展望

在过去３０年中美国科学家已经产生了一种倾向性看法，即认为金属矿床是大尺度地质作用的产物（例如板块构造和盆地卤水区域性迁移）．在这一时期内，矿业公司和科学家空前地致力于金矿床研究。除了国内金矿之外，他们还特别注意研究国外的矿床。流体包裹体、绝对年龄、稳定同位素研究、计算机模拟、遥感和地球物理方法已经成为广泛应用的技术手段。当今普遍研究的矿床课题范围很广泛：包括斑岩型矿床、密西西比盆地型矿床、金刚石岩管、深海块状硫化物矿床、含贵金属煤、矿化页岩和一些新矿床类型（例如奥林匹克坝型矿床，卡林型矿床和Ｎｉ－Ｍｏ－ＰＧＥ－Ａｕ硫化物矿床）。在未来十年内，有可能继续注意国外金属矿床和金矿的研究。新的重要矿床发现（尤其是在基底地体、海洋和国外）正拭目以待。与沉积盆地中流体的最近研究相比较，可以预料扩大环境研究也具有重要意义。与此同时，象类似于接受板块构造理论一样，地球深部创造性研究可以使矿床成因的理性认识有所突破。