月鳢个体发育早期4种同工酶的初步研究

采用垂直板聚丙烯酰胺凝胶电泳技术,对月鳢早期(从未受精卵至卵黄吸尽期)8个发育阶段的LDH、MDH、ADH、EST同工酶进行研究。结果表明:月鳢的早期发育阶段ADH酶谱相对稳定,均有两条谱带;LDH、MDH和EST三种同工酶的酶谱在神经胚期前均无明显变化,此后随发育进程逐渐复杂。     

Isozymes Analysis of the Golden Cuttlefish Sepia esculenta（Cephalopoda ： Sepiidae）

Thirty-nine isozymes in four tissues (mantle muscle, buccal bulb muscle, eye and liver) of Sepia esculenta were screened for enzymatic analysis using starch gel electrophoretic technique. Eighteen enzymes (G3PDH, LDH, MDH, MEP, IDHP, PGDH, GRS, NP, AAT, CK, AK, EST, ALP, ACP, FBP, MPI, GPI and PGM) show strong activities and good convergence in zymogram. They are proved to be suitable genetic markers in Sepia esculenta. Among the tissues used, mantle muscle is the best for electrophoretic analysis of isozymes. Eye and liver are fairly good for some special enzymes, such as LDH, EST, MPI, etc. Twenty-six loci are detected. The proportion of polymorphic loci is 0.115 in the Qingdao sample and 0.153 in the Rizhao sample (P<0.99). The mean values of the observed and expected heterozygosity per locus of Qingdao sample are 0.016 and 0.017, while those of the Rizhao sample are 0.023 and 0.025 respectively.     

Smoothed particle hydrodynamics pore-scale simulations of unstable immiscible flow in porous media

We have conducted a series of high-resolution numerical experiments using the Pair-Wise Force Smoothed Particle Hydrodynamics (PF-SPH) multiphase flow model. First, we derived analytical expressions relating parameters in the PF-SPH model to the surface tension and static contact angle. Next, we used the model to study viscous fingering, capillary fingering, and stable displacement of immiscible fluids in porous media for a wide range of capillary numbers and viscosity ratios. We demonstrated that the steady state saturation profiles and the boundaries of viscous fingering, capillary fingering, and stable displacement regions compare favorably with micromodel laboratory experimental results. For a displacing fluid with low viscosity, we observed that the displacement pattern changes from viscous fingering to stable displacement with increasing injection rate. When a high viscosity fluid is injected, transition behavior from capillary fingering to stable displacement occurred as the flow rate was increased. These observations are also in agreement with the results of the micromodel laboratory experiments.     

中华白海豚SRAP分子标记多态性的初步研究

首次将SRAP(sequence-related amplified polymorphism)方法引入中华白海豚(Sousa chinensis)多态性研究中,利用高分辨率的毛细管凝胶电泳分析了模板DNA、Mg2+、dNTP、引物、Taq DNA聚合酶等因素对SRAP-PCR扩增结果的影响.确定了me1-em5为扩增中华白海豚基因组DNA的最佳引物对.并进一步确立了适合中华白海豚的SRAP最佳反应体系:25 mm3体系中,模板DNA浓度为0.8 ng/mm3,Mg2+浓度为1.0 mmol/dm3,dNTP浓度为0.1 mmol/dm3,引物浓度为0.2μmol/dm3,Taq DNA聚合酶浓度为0.04 U/mm3.利用该反应体系对10个白海豚样品进行SRAP分析的结果表明,不同样品间DNA谱带清晰、多态性丰富.证实该体系稳定可靠,可以用于中华白海豚的分子标记研究.     

The two species of sprat in New Zealand waters (Sprattus antipodum and S. muelleri)

Two broadly sympatric species of sprat are shown to inhabit New Zealand waters, the more slender Sprattus antipodum (Hector, 1872) and the more common and deeper‐bodied S. muelleri (Klunzinger, 1872). Overlap in most morphometric and meristic characters had earlier led to their synonymy, but recent protein analysis suggested otherwise. This is now confirmed by distinct differences in shape and dentition of the basihyal plate, vertebral numbers, scale sculpture, and fresh colour. The five known species of Sprattus are keyed and the genus diagnosed and discussed.     

大菱鲆(Scophthalmus maximus)低温胁迫耐受性能与体表蛋白组学研究

采用急性低温胁迫实验方法,通过对实验鱼的死亡率、死亡历时、摄食量以及呼吸频率等耐寒指标进行比较分析,并由此分析结果判断幼鱼的低温临界温度为0℃,在此温度基础上,利用双向电泳技术,对大菱鲆(Scophthalmus maximus)幼鱼进行体表蛋白水平上的耐受机理研究。根据低温胁迫组和常温对照组机体表皮蛋白组图谱差异进行比较分析。结果表明,低温胁迫后蛋白发生了显著变化。从中挑选四个差异蛋白点进行肽指纹图谱(MALDI-TOF-MS)分析,采用PMF技术和MASCOT、NCBI网站提供的检索工具进行鉴定,结果显示,低温胁迫组大菱鲆表皮MLC和Mimecan前体蛋白表达显著上调,而typeⅡ角蛋白表达显著下调。大菱鲆对低温胁迫是一个复杂的网络反应,涉及很多蛋白质的参与,这些低温响应蛋白在大菱鲆对低温胁迫的抗性反应中起到重要的作用。     

Three-phase measurements of oil and gas trapping in sand packs

We measure the trapped saturations of oil and gas as a function of initial saturation in water-wet sand packs. We start with a water-saturated column and inject octane (oil), while water and oil are produced from the bottom. Once water production has ceased, air (gas) then enters from the top, allowing oil and gas to drain under gravity for different times. Finally water is then injected from the bottom to trap both oil and gas. The columns are sliced and the fluids analyzed using gas chromatography. We find that for high initial gas saturations more gas can be trapped in the presence of oil than in a two-phase (gas/water) system. The residual gas saturation can be over 20% compared to 14% in two-phase flow [Al Mansoori SK, Iglauer S, Pentland CH, Bijeljic B, Blunt MJ. Measurements of non-wetting phase trapping applied to carbon dioxide storage. Energy Procedia 2009;1(1):3173–80]. This is unlike previous measurements on consolidated media, where the trapped gas saturation is either similar or lower to that reached in an equivalent two-phase experiment. For lower initial gas saturation, the amount of trapping follows the initial-residual trend seen in two-phase experiments. The amount of oil trapped is insensitive to initial gas saturation or the amount of gas that is trapped, again in contrast to measurements on consolidated media. More oil is trapped than would be predicted from an equivalent two-phase (oil/water) system, although the trapped saturation is never larger than the maximum reached in two-phase flow (around 11%) [Pentland CH, Al Mansoori SK, Iglauer S, Bijeljic B, Blunt MJ. Measurement of non-wetting phase trapping in sand packs. In: SPE 115697, proceedings of the SPE annual technical conference and exhibition, Denver, Colorado, USA; 21–24 September 2008]. These initially surprising results are explained in the context of oil layer stability and the competition between snap-off and piston-like advance. In two-phase systems, displacement is principally by cooperative piston-like advance with relatively little trapping, whereas in consolidated media snap-off is generally more significant. However, oil layer collapse events during three-phase waterflooding rapidly trap the oil which acts as a barrier to direct water/gas displacement, except by snap-off, leading to enhanced gas trapping.     

Interfacial tension measurements and wettability evaluation for geological CO2 storage

Interfacial interactions, namely interfacial tension, wettability, capillarity and interfacial mass transfer are known to govern fluid distribution and behavior in porous media. Therefore the interfacial interactions between CO₂, brine and oil and/or gas reservoirs have a significant influence on the effectiveness of any CO₂ storage operations. However, data and knowledge of interfacial properties in storage conditions are scarce. This issue becomes particularly true in the case of deep saline aquifers where limited, economically driven, data collection and archiving are available. In this paper, we present a complete set of brine–CO₂ interfacial tension data at pressure, temperature and salinity conditions, representative of a CO₂ storage operation. A semi-empirical correlation is proposed to calculate the interfacial tension from the experimental data. Wettability is studied at pore scale, using glass micromodels in order to track fluids distribution as a function of the thermodynamic properties and wettability conditions for water–CO₂ systems. With this approach, we show that, in strongly hydrophilic porous media, the CO₂ does not wet the solid surface whereas; if the porous media has less hydrophilic properties the CO₂ significantly wets the surface.     

Scale dependent dynamic capillary pressure effect for two-phase flow in porous media

Causes and effects of non-uniqueness in capillary pressure and saturation (P^c–S) relationship in porous media are of considerable concern to researchers of two-phase flow. In particular, a significant amounts of discussion have been generated regarding a parameter termed as dynamic coefficient (τ) which has been proposed for inclusion in the functional dependence of P^c–S relationship to quantify dynamic P^c and its relation with time derivative of saturation. While the dependence of the coefficient on fluid and porous media properties is less controversial, its relation to domain scale appears to be dependent on artefacts of experiments, mathematical models and the intra-domain averaging techniques. In an attempt to establish the reality of the scale dependency of the τ–S relationships, we carry out a series of well-defined laboratory experiments to determine τ–S relationships using three different sizes of cylindrical porous domains of silica sand. In this paper, we present our findings on the scale dependence of τ and its relation to high viscosity ratio (μ_r) silicone oil–water system, where μ_r is defined as the viscosity of non-wetting phase over that of the wetting phase. An order of magnitude increase in the value of τ was observed across various μ_r and domain scales. Also, an order of magnitude increase in τ is observed when τ at the top and the bottom sections in a domain are compared. Viscosity ratio and domain scales are found to have similar effects on the trend in τ–S relationship. We carry out a dimensional analysis of τ which shows how different variables, e.g., dimensionless τ and dimensionless domain volume (scale), may be correlated and provides a means to determine the influences of relevant variables on τ. A scaling relationship for τ was derived from the dimensionless analysis which was then validated against independent literature data. This showed that the τ–S relationships obtained from the literature and the scaling relationship match reasonably well.     

Penetration of molten iron alloy into the lower mantle phase

The core–mantle boundary is the only interface where the metallic core and the silicate mantle interact physically and chemically. Many geophysical anomalies such as low shear velocity and high electrical conductivity have been observed at the bottom of the mantle. Perturbations in the Earth's rotation rate at decadal time periods require the existence of a thin conductive layer with a conductance of 10⁸ S. Substantial additions of molten iron from the outer core into the mantle may produce these geophysical anomalies. Although iron enrichment by penetration has only been observed in (Mg,Fe)O, the second dominant mineral in the lower mantle, the penetration process leading to iron enrichment in the silicate mantle has not been experimentally confirmed. In this study, high-pressure and high-temperature experiments were conducted to investigate the penetration of molten iron alloy into lower mantle phases; postspinel, polycrystalline bridgmanite and polycrystalline (Mg,Fe)O. At the interface between (Mg,Fe)O aggregate and molten iron alloy, liquid metal penetrated the (Mg,Fe)O aggregate along grain boundaries and formed a thin layer containing metal-rich blobs. In contrast, no penetration of molten iron alloy was observed at the interface between molten iron alloy and silicate phases. Penetration of liquid iron alloy into the (Mg,Fe)O aggregate is caused by the capillarity phenomenon or Mullins–Sekerka instability. Neither mechanism occurs at the boundary of pure polycrystalline MgO, indicating that the FeO in (Mg,Fe)O plays an essential role in this phenomenon. Infiltration of molten iron alloy along grain boundaries (capillarity phenomenon) is the dominant process and precedes penetration due to the Mullins–Sekerka instability. The capillarity phenomenon is governed by the balance of forces between surface tension and gravity. In the case where the ultralow velocity zone (ULVZ) with a low shear velocity is composed of Fe-rich (Mg,Fe)O, the maximum penetration distance of molten iron alloy by capillary rise is limited to 20 m. The addition of iron-rich melt to the base of the mantle is therefore unlikely to be the main cause of the high conductance of the CMB region predicted from decadal variation of the length of day. Furthermore, the absence of molten iron alloy penetration into silicate phases does not allow an extensive modification of the chemical composition of the mantle by core–mantle interaction.