藻类磷酸甘露糖异构酶基因的序列结构特点及系统进化分析

磷酸甘露糖异构酶基因(phosphomannose isomerase,PMI)编码磷酸甘露糖异构酶(PMI),可逆催化甘露糖-6-磷酸和果糖-6-磷酸之间的相互转化,在GDP-D-甘露糖的合成中起重要的作用,后者是生物体合成糖蛋白和糖脂必需的前体物质。本文根据在Genbank中已经登录的部分藻类PMI基因序列,与部分细菌、真菌、植物和动物的PMI基因序列做比较,研究其进化趋势和规律及其基因结构,为以后在大型藻类中研究该基因奠定基础。系统进化分析表明,藻类的PMI基因有2个进化方向,绿藻类的PMI基因与高等植物的进化趋势一致;而杂色藻类(硅藻和褐藻)则单独形成一个进化分支。多序列比对表明,磷酸甘露糖异构酶蛋白有3个保守区,其中有4个氨基酸残基位点是金属离子结合位点,分别为2个Glu和2个His。对部分藻类的PMI基因进行结构分析表明:在比较低等的藻类中,PMI基因没有内含子插入,而较高等的藻类中则有不同数目和长度的内含子插入。对部分藻类PMI基因的生物信息学分析结果显示,PMI基因编码的蛋白为酸性蛋白,分子量在40到60kDa之间;二级结构中均以α-螺旋和无规则卷曲为主;三级结构与二级结构相吻合。     

北极和南极表面温度对中低纬度海洋热强迫的响应

利用耦合了平板海洋模型的全球气候模式进行了大量的格林函数实验,以探究两极地区对于施加在中低纬度海域的热强迫的气候响应。结果表明,北极地区的气候不仅受到距离较近的北太平洋与北大西洋的影响,远离北极的热带太平洋以及南太平洋也对其气候有显著的影响,南极地区的气候则主要是受到邻近的南大洋的影响。通过经验正交函数法的进一步分析发现,北极响应最显著的区域包括波弗特海(Beaufort Sea)、拉普捷夫海(Laptev Sea)以及北极中心区附近;南极地区的响应主要集中在别林斯高晋海(Bellinsgauzen Sea)区域。另外,利用温度归因法对辐射反馈过程和大气能量输运分解发现,北极地区表面温度的响应主要是受到了反照率反馈以及垂直递减率反馈的影响,而南极地区的响应则主要是反照率反馈发挥了作用。     

CdTe量子点荧光猝灭法测定赤泥中痕量镍

Cd Te量子点具有荧光强度高和稳定性好的优点,应用Cd Te量子点荧光猝灭法分析基体复杂的样品,需要有效分离对测定干扰的金属元素和高效富集待测元素。本文以巯基乙酸(TGA)作稳定剂,采用水相合成法制备了巯基乙酸修饰的Cd Te量子点,基于镍离子在p H=10.0硼砂缓冲溶液中对Cd Te量子点的荧光具有较强猝灭作用,建立了一种测定赤泥中痕量镍的荧光光度方法。荧光猝灭反应的最佳实验条件为:Cd Te量子点的浓度3.0×10-4mol/L,反应温度为室温,反应时间10 min,在此条件下镍离子浓度在2.0×10-7~7.8×10-5mol/L范围内与Cd Te量子点的相对荧光强度呈良好的线性关系;方法检出限为1.5×10-7mol/L。本方法针对Fe3+、Co2+、Cu2+等主要基体金属元素允许量低的问题,采用25%的2-羟基-4-仲辛氧基二苯甲酮肟(N530)磺化煤油萃取回收滤液中的Ni2+,镍回收率达到99%以上;赤泥中痕量镍的测定结果与催化光度法相符,加标回收率为98.3%-104.2%。     

Geological Features, Mineralization Types and Metallogenic Setting of the Phlaythong Large Iron Deposit, Southern Laos

<正>The Phlaythong large iron deposit in Shampasak of southern Laos,is located in the Kon Tum microblock(Fig.1A),central-southern part of the Indo-China block,and the geographic coordinate of the central mining area is 14°43′04″N and 106°07′02″E.Intensive tectonic and magmatic activities of multiple periods developed in this region,especially in Mesozoic and Cenozoic,which are closely     

Coupled DEM-CFD investigation on the formation of landslide dams in narrow rivers

Large-scale landslide dams can induce significant hazards to human lives by blocking the river flows and causing inundation upstream. They may trigger severe outburst flooding that may devastate downstream areas once failed. Thus, the advancement in understanding the formation of landslide dams is highly necessary. This paper presents 3D numerical investigations of the formation of landslide dams in open fluid channels via the discrete element method (DEM) coupled with computational fluid dynamics (CFD). By employing this model, the influence of flow velocity on granular depositional morphology has been clarified. As the grains settle downwards in the fluid channel, positive excess water pressures are generated at the bottom region, reducing the total forces acting on the granular mass. In the meantime, the particle sedimentations into the fluid channel with high impacting velocities can generate fluid streams to flow backwards and forwards. The coupled hydraulic effects of excess water pressure and fluid flow would entrain the solid grains to move long distances along the channel. For simulations using different flow velocities, the larger the flow velocity is, the further distance the grains can be transported to. In this process, the solid grains move as a series of surges, with decreasing deposit lengths for the successive surges. The granular flux into the fluid channel has very little influence on the depositional pattern of particles, while it affects the particle–fluid interactions significantly. The results obtained from the DEM-CFD coupled simulations can reasonably explain the mechanisms of granular transportation and deposition in the formation of landslide dams in narrow rivers.     

哀牢山金矿带北段马邓岩群外麦地岩组浅变质岩系中发现金矿体群

<正>1研究目的(Objective)哀牢山金矿带处于哀牢山双变质带南西侧的含金低级变质带中,夹持于北西向的哀牢山断裂与九甲—阿墨江断裂之间(图1a)。该金矿带可分为北矿段和南矿段,以往将北矿段划分为九甲—老王寨—金厂金成矿亚带(西亚带)和大乾树—二台坡金成矿亚带(东亚带)。其中,西亚带为主要的成矿带,已知矿床产出较为集中,主要有镇沅老王寨、东瓜林、浪泥塘、和平丫口、库独木、搭桥箐     

冀东下营坊地区晚古生代富碱侵入岩锆石U-Pb年代学、岩石地球化学及其地质意义

富碱侵入岩具有重要的地质和矿产意义,倍受学者关注。冀东地区晚古生代钙碱性岩浆岩十分发育,而碱性岩少见,笔者首次在冀东下营坊地区识别出一批与金(铜铅锌银)多金属矿化有关的晚古生代中晚期的富碱侵入岩体。通过锆石LA-ICP-MS U-Pb测年,获得下营坊地区三处富碱侵入岩的侵位年龄分别为300.0±1.5Ma、299.3±2.1Ma、300.0±2.0Ma,侵位时间显示这些岩浆岩均为晚石炭世末—早二叠世的产物。岩石地球化学特征显示富碱(K2O+Na2O8%),稀土元素含量较高,并强烈富集轻稀土,指示其具有富碱侵入岩的基本特征。下营坊富碱侵入岩富集大离子亲石元素,高La/Yb比,较高的La/Sm比值且变化范围大(5),低Y,Eu异常不明显等特点,表明其源区可能与富集地幔有关,并可能受到俯冲板片脱水所释放流(熔)体的影响,在岩浆的侵位过程中可能受到地壳物质的混染。由成岩时代结合区域构造演化历史推断,该地区富碱侵入岩很可能与古生代期间古亚洲洋板块向华北板块俯冲有关,并形成于由俯冲板块后撤的伸展环境。     

Open tensile fractures at depth in anticlines: A case study in the Tarim basin,NW China

Understanding fracture openness in the Earth's crust is crucial for understanding fracture properties and their impact on fluid flow and potentially also in reservoir modelling. Here, we present cases showing the presence of open tensile fractures at depth in anticlines by integrating borehole imaging logs, core observations, casting sections, physical modelling, in‐situ stress analysis and production data in petroleum wells, and analysing the time of fracturing by fluid inclusion analysis. The data come from the Cretaceous Bashejiqike Formation in the Kuqa Depression, Tarim basin; its current depth varies between 6,000 and 8,100 m. The results show that tensile fractures are the main fracture type in the studied formation and that their hydraulic conductivity is poorly affected by the current maximum horizontal stress direction. Furthermore, we find that fracture development is uninterrupted during continued anticline folding, although there is a dominant time of fracturing.     

华南地区奥陶纪头足类生物相及其分区

在研究华南地区奥陶纪头足类生态特征基础上,根据头足类的生态类型及其保存条件等特征,识别出18个头足类生物相,即开阔台地[WT5”BX]Proterocameroceras生物相,局限台地Pseudoectenolites-Xiadongoceras生物相,开阔台地Retroclitendoceras-Pararetrocli tendoceras生物相,开阔台地Pronajaceras-Mamagouceras生物相,陆棚斜坡—盆地Cyclostomiceras-Bactroceras生物相,开阔台地 Cameroceras-Cyrtovaginoceras生物相,开阔台地 Coreanoceras-Manchuroceras生物相,陆棚斜坡—盆地Kaipingoceras-Kyminoceras生物相,内陆棚Bathmoceras-Protocycloceras生物相,中部陆棚Dideroceras-Ancistroceras生物相,深水陆棚 Lituites-Cyclolituites 生物相,滞流盆地Lituites-Trilacinoceras生物相,深水盆地Paraendoceras-Sactorthoceras,深水陆棚Sinoceras-Michelinoceras-Disoceras生物相,深水陆棚Beloitoceras-Jiangshanoceras生物相,深水陆棚—盆地Eurasiaticoceras生物相,浅海陆棚—斜坡Jiangxiceras-Yushanoceras生物相,深水盆地Michelinoceras[WT5”BZ]生物相,并阐述各生物相的组成、生态特征及其生态环境。根据头足类生物相在时间和空间上的组合规律,划分出3个头足类生物相区,即扬子生物相区、黔东—湘西生物相区（过渡型生物相区）和湘中—浙西生物相区,并讨论了各生物相区在不同时期内头足类生态类型和生物相分异特征、海平面升降、环境演变特征以及其与油气的关系。认为在低海平面或海平面下降阶段中生物相分异明显,而在高海平面阶段中则分异较小。     

Electro-osmotic permeability model based on ions migration

Acta Geotechnica - Electro-osmotic permeability is a very important parameter in soil drainage and electrochemical remediation. The present widely used equation for calculating the electro-osmotic...