Phylogenetic and systematic study of the genus Bombina (Amphibia : Anura : Bombinatoridae): New insights from molecular data

Phylogenetic relationships and systematics of the eight currently recognized species of the genus Bombina were investigated using four mitochondrial gene fragments (16S rRNA, 12S rRNA, ND4-tRNA(LEU), and cytochrome b). We prepared two different concatenat

Systematic study of the pi(-)/pi(+) ratio in heavy-ion collisions with the same neutron/proton ratio but different masses

A systematic study of the pi(-)/pi(+) ratio in heavy-ion collisions with the same neutron/proton ratio but different masses can help single out effects of the nuclear mean field on pion production. Based on simulations using the IBUU04 transport model, it is found that the pi(-)/pi(+) ratio in head-on collisions of Ca-48 + Ca-48, Sn-124 + Sn-124, and Au-197 + Au-197 at beam energies from 0.25 to 0.6 GeV/nucleon increases with increasing the system size or decreasing the beam energies. A comprehensive analysis of the dynamical isospin fractionation and the pi(-)/pi(+) ratio as well as their time evolution and spatial distributions demonstrates clearly that the pi(-)/pi(+) ratio is an effective probe of the high-density behavior of the nuclear symmetry energy.

Systematic study on alpha decay half-lives of superheavy nuclei

The a-decay half-lives of a set of superheavy nuclear isotope chain from Z = 105 to 120 have been analyzed systematically within the WKB method, and some nuclear structure features are found. The decay barriers have been determined in the quasi-molecular shape path within the Generalized Liquid Drop Model (GLDM) including the proximity effects between nucleons in a neck and the mass and charge asymmetry. The results are in reasonable agreement with the published experimental data for the alpha decay half-lives of isotopes of charge 112, 114, and 116, of the element 294118 and of some decay products. A comparison of present calculations with the results by the DDM3Y effective interaction and by the Viola-Seaborg Sobiczewski (VSS) formulae is also made. The experimental a decay half lives all stand in between the GLDM calculations and VSS formula results. This demonstrates the possibility of these models to provide reasonable estimates for the half-lives of nuclear decays by a emissions for the domain of SHN. The half-lives of these new nuclei are thus well tested from the reasonable consistence of the macroscopic, the microscopic, the empirical formulae and the experimental data. This also shows that the present data of SHN themselves are consistent. It could suggest that the present experimental claims on the existence of new elements Z = 110 similar to 118 are reliable. It is expected that greater deviations of a few SHN between the data and the model may be eliminated by further improvements on the precision of the measurements.

Systematic study of properties of Hs nuclei

The ground-state properties of Hs nuclei are studied in the framework of the relativistic meanfield theory. We find that the more relatively stable isotopes are located on the proton abundant side of the isotopic chain. The last stable nucleus near the proton drip line is probably the (255)Hs nucleus. The alpha-decay half-lives of Hs nuclei are predicted, and together with the evaluation of the spontaneous-fission half-lives it is shown that the nuclei, which are possibly stable against spontaneous fission are (263-274)Hs. This is in coincidence with the larger binding energies per nucleon. If (271-274)Hs can be synthesized and identified, only those nuclei from the upper Z = 118 isotopic chain, which are lighter than the nucleus (294)118, and those nuclei in the corresponding alpha-decay chain lead to Hs nuclei. The most stable unknown Hs nucleus is (268)Hs. The density-dependent delta interaction pairing is used to improve the BCS pairing correction, which results in more reasonable single-particle energy level distributions and nucleon occupation probabilities. It is shown that the properties of nuclei in the superheavy region can be described with this interaction.

Systematic study of the transfer of amino acids across the water/1,2-dichloroethane interface facilitated by dibenzo-18-crown-6

Facilitated ion transfer reactions of 20 amino acids with di.benzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically using cyclic voltammetry. It was found that there were only 10 amino acids, that is, Leu, Val, Ile, Phe, Trp, Met, Ala, Gly, Cys, Gln (in brief), whose protonated forms as cations can give well-defined facilitated ion transfer voltammograms within the potential window, and the reaction pathway was proven to be consistent with the transfer by interfacial complexation/dissociation (TIC/TID) mechanisms. The association constants of DB 18C6 with different amino acids in the DCE (beta(0)), and the kinetic parameters of reaction were evaluated based on the steady-state voltammetry of micro- or nano-pipets, respectively The experimental results demonstrated that the selectivity of complexation of protonated amino acid by DB18C6 compared with that of alkali metal cations was low, which can be attributed to the vicinal effect arising from steric hindrance introduced by their side group and the steric bulk effect by lipophilic stabilization.

Self-assembled monolayer growth of phospholipids on hydrophobic surface toward mimetic biomembranes: Scanning probe microscopy study

Atomic force microscopy (AFM) and lateral force microscopy (LFM) were used simultaneously to analyze a model membrane bilayer structure consisting of a phospholipid outer monolayer deposited onto organosilane-derivatized mica surfaces, which were constructed by using painting and self-assembly methods. The phospholipid used as outer monolayer was dimyristoylphosphatidylcholine (DMPC). The hydrocarbon-covered substrate that formed the inner half bilayer was composed of a self-assembly monolayer (SAM) of octadecyltrichloroorganosilane (OTS) on mica. SAMs of DMPC were formed by exposing hydrophobic mica to a solution of DMPC in decane/isobutanol and subsequently immersing into pure water. AFM images of samples immersed in solution for varying exposure times showed that before forming a complete monolayer the molecules aggregated into dense islands (2.2-2.6 nm high) on the surface. The islands had a compact and rounded morphology. LFM, coupled with topographic data obtained with the atomic force mode, had made possible the distinction between DMPC and OTS. The rate constant of DMPC growth was calculated. This is the first systematic study of the SAM formation of DMPC by AFM and LFM imaging. It reveals more direct information about the film morphology than previous studies with conventional surface analytical techniques such as infrared spectroscopy, X-ray, or fluorescence microscopy.

Simulations of Mechanical Behavior of Polycrystalline Copper with Nano-Twins

Mechanical behavior and microstructure evolution of polycrystalline copper with nano-twins were investigated in the present work by finite element simulations. The fracture of grain boundaries are described by a cohesive interface constitutive model based on the strain gradient plasticity theory. A systematic study of the strength and ductility for different grain sizes and twin lamellae distributions is performed. The results show that the material strength and ductility strongly depend on the grain size and the distribution of twin lamellae microstructures in the polycrystalline copper.

Transitions Between Different Contact Models

The transitions between the different contact models which include the Hertz, Bradley, Johnson-Kendall-Roberts (JKR), Derjaguin-Muller-Toporov (DMT) and Maugis-Dugdale (MD) models are revealed by analyzing their contact pressure profiles and surface interactions. Inside the contact area, surface interaction/adhesion induces tensile contact pressure around the contact edge. Outside the contact area, whether or not to consider the surface interaction has a significant influence on the contact system equilibrium. The difference in contact pressure due to the surface interaction inside the contact area and the equilibrium influenced by the surface interaction outside the contact area are physically responsible for the different results of the different models. A systematic study on the transitions between different models is shown by analyzing the contact pressure profiles and the surface interactions both inside and outside the contact area. The definitions of contact radius and the flatness of contact surfaces are also discussed. (C) Koninklijke Brill NV, Leiden, 2008.

Theoretical and experimental studies of the bell-jar-top inductively coupled plasma

The present paper describes a systematic study of argon plasmas in a bell-jar inductively coupled plasma (ICP) source over the range of pressure 5-20 mtorr and power input 0.2-0.5 kW, Experimental measurements as well as results of numerical simulations are presented. The models used in the study include the well-known global balance model (or the global model) as well as a detailed two-dimensional (2-D) fluid model of the system, The global model is able to provide reasonably accurate values for the global electron temperature and plasma density, The 2-D model provides spatial distributions of various plasma parameters that make it possible to compare with data measured in the experiments, The experimental measurements were obtained using a tuned Langmuir double-probe technique to reduce the RF interference and obtain the light versus current (I-V) characteristics of the probe. Time-averaged electron temperature and plasma density were measured for various combinations of pressure and applied RF power, The predictions of the 2-D model were found to be in good qualitative agreement with measured data, It was found that the electron temperature distribution T-e was more or less uniform in the chamber, It was also seen that the electron temperature depends primarily on pressure, but is almost independent of the power input, except in the very low-pressure regime. The plasma density goes up almost linearly with the power input.

Intrinsic correlation between fragility and bulk modulus in metallic glasses

A systematic study on the available data of 26 metallic glasses shows that there is an intrinsic correlation between fragility of a liquid and bulk modulus of its glass. The underlying physics can be rationalized within the formalism of potential energy landscape thermodynamics. It is surprising to find that the linear correlation between the fragility and the bulk-shear modulus ratio exists strictly at either absolute zero temperature or very high frequency. Further analyses indicate that a real flow event in bulk metallic glasses is shear dominant, and fragility is in inverse proportion to shear-induced bulk dilatation. Finally, extension of these findings to nonmetallic glasses is discussed.

毛茛科升麻族（广义）的系统学研究

本文利用多种实验手段，对升麻族(Cimicifugeae,s.l.)的节部维管系统、花瓣、花粉、种皮及细胞学性状进行综合分析，根据这些性状的演化趋势，探讨了升麻族的范围、系统位置和属间关系。 通过对节部维管系统的研究，作者发现升度族的节均为多隙节类型，填补了铁破锣属 (Beesia)和黄三七属(Souliea)叶隙节资料的空白。 通过对花瓣式样及其脉序类型的研究，提出了升麻族的花瓣演化路线，充实了毛莨科(Ranunculaceae)的花瓣来源于雄蕊这一观点，认为毛莨科的花瓣主要不源于雄蕊的药隔部分，具二歧脉的花瓣由药隔不突出的基着药雄蕊演化而来，而具三出脉的花瓣由药隔发达、有时先端突出的雄蕊演化而来。 作者除在扫描电镜下观察了升麻族的花粉形态外，还首次在透射电镜下观察了升麻族所有5属的花数外壁结构，发现黄三七属的花粉不仅具独特的条纹——网状纹饰，且其外壁具半覆盖层;在细胞学研究中，发现黄三七属的细胞间期核形态明显不同于金莲花亚科(Helleboroideae)的其它属，为复杂染色中心型(Complex chromocenter type)和棒状前染色体型(Rod prochromosome type)间的过渡类型。综合考虑本属和黄连属(Coptis)的体态、中期染色体形态及血清学证据，作者认为黄三七属是升麻族中的一个特化类群，是大（R-型）染色体往小（T-型）染色体演化的一个过渡类群，本属很可能与黄连族(Coptideae)植物关系较为密切。此外，作者借助扫描电镜的观察，发现升麻族的种皮向两个方向演化，一支适应风传播，表现为种翅发达;另一支适应动物传播，抗消化，表现为种皮坚硬，表面具密集的瘤状突起。 通过对升麻族地理分布格局的研究，作者认为本族可能是起源于东亚的一群极为古老的毛莨科植物，由毛莨科的祖先直接演化而来。铁破锣属和黄三七属很可能起源于中国西南山地。 最后作者基于自已的多种实验结果、前人的植化和细胞学资料，不同意铁破锣属放在金莲花族(Trollieae)或铁筷子族(Helleboreae)，对Tamura的升麻族概论及系统关系进行重大修改，不赞成升麻族来自驴蹄草属(Caltha)这一观点，而支持王文采的系统，把 铁破锣属移入升麻族，并认为修改过的升麻族是毛莨科中一个非常自然而以特殊的类群，除一系列形态特征不同于金莲花亚科的其它属外，该族植物不含毛莨科特征性成分—毛莨甙或木兰花碱，而含有独特的四环三萜式成分(Anemonopsis 是否含此成分，尚待研究)及呋喃色酮类化合物，染色体组分中，具5-6对大m的染色体，应独立作为一个新亚新——升麻亚科(Cimicifugoideae)，推测本亚科与金莲花亚科均来自毛茛科的祖先型。升麻亚科中，铁破锣属保留了很多原始特征，如单叶、无花瓣等，作者将其提升为族—铁破锣族(Beesieae)。伴随单叶往复叶的演化过程，升麻亚科的原始群（类似铁破锣族）分化为两支：一支的染色体演化较慢，但果实和种显示出明显的分化，形成升麻族(Cimicifugeae, s.str.)，包括垂果升麻属(Anemono psis)、升麻属和类叶升麻属;另一支的花瓣、花粉和染色体的演化水平较高，形成黄三七属，作者将其独立为一个新族——黄三七族(Soulieae)，除上述系统处理外，本文提供了包括升麻亚科所有属种的检索表。

国产贝母属（百合科）的系统学研究

作者通过实地调查，栽培观察，大量查阅标本，对国产贝母属(Fritillaria L.)的形态性状作了深入的分析，认为贝母属中植株大小，茎生叶先端卷曲与否，花的数目、花梗的长短、花被片颜色等性状易受生境的影响;而鳞茎所具鳞片的数目，植株最下一轮叶的形状及排列，花部蜜腺的形状，花柱柱头的分裂程度，雄蕊花丝在发育完后的长短，蒴果的形状等性状受生境的影响较小，但在栽培情况下，这些性状有时也会发生变化．此外，作者首次报道了部分国产贝母属种类的核型和花粉形态．在此基础上对我国贝母属进行了系统整理，将正式发表的138个分类名称（包括80个种、52个变种、5个变型、1个栽培变型）归并成24种l变种，并对国产贝母组(Seclion Fritillaria)的种间关系作了初步探讨;同时，对该属的次级分类也作了修订．根据有关，F.karelinii花粉学和细胞学资料，以及邻近4个种的形态特征及分布特点，我们支持J.G..Baker(1874)的观点将该类群保留在贝母属内而不同意A.S.Lozin-Lozinskaya(1935)，A.Takhtajan(1987)将其单立成属也不同意W.B.Turrill &J.R.Sealy(1980)将其并入贝母组(Sect.Fritillaria)，而将该类群做为贝母属中的一个新组——砂贝母组(Sect.Rhinopetalum (Fish. ex Alex.) Y.B.Luo)．并认为该组与贝母组关系较近．作者通过上述工作及查阅世界各地有关贝母属的文献，认为贝母属内最原始的类群是Sect. Fritillaria，而Sect.Petillium，Sect.Rhinopetalum和Sect.Theresia是演化水平中等的类群．Sect.Liliorhiza则是演化水平最高的一类．通过对该属组(Section)级及种级分布式样的分析，认为伊朗一土兰区不仅是组的多度中心，并且也是多样化中心;在种级水平上，地中海区是分布的多度中心，而种级多样化中心则在伊朗一土兰区;此外，在伊朗一土兰区还保留着一些较原始的类群，因而，该区可能是贝母属的起源中心，最后，作者对贝母属的起源时间、散布途径及现代分布格局形成的原因进行了初步探讨．

中国苏铁属系统学研究

本文系统地总结了分布于我国的苏铁属13种植物的形态和地理分布，并在此基础上进行了解剖，微形态和生化分析。此外，还用表征分类的方法探讨了属内亲缘关系。结合古植物和古地理的知识对性状演化趋势和现代分布格局的成因进行了讨论。本文主要结论如下： 1．从种子蛋白电泳结果表明，所有现存苏铁类植物在39.8kd- 49.5kd之间均有—连续分布的混合多肽，为苏铁类所特有。杂种后代在种子蛋白电泳结果上可以表现出来。种子蛋白多肽分布在苏铁属内差异非常小，在属间差异明显，根据属间多肽距离确定苏铁属的分化较早，系统位置比较孤立。 2．形态特征表征分类结果表明攀枝花苏铁、台东苏铁、苏铁和篦齿苏铁应分在一组Sect.Asiotientales。组Sect.lndosinensis中的广东苏铁与、海南苏铁的亲缘关系较近。通过对叶表皮的观察，发现苏铁屑内植物有两种气孔类型：一种是以C.revoluta为代表的具气孔外拱盖的I型气孔，II型气孔无气孔外拱盖，为属内多数植物所具有;叶解剖的结果表明叉叶苏铁和多歧苏铁小叶中具树脂道，叶表皮和叶解剖的结果都支持台东苏铁成立。 3.攀枝花苏铁与把关河苏铁应为同一种，贵州苏铁与四川苏铁很相似，初步处理为一种，采用C.szechuanensis为学名。 4．苏铁类性状演化不均衡，染色体进化与形态进化不同步。结合化石证据确定，具掌状大孢子叶、二叉分枝脉的叉叶苏铁是现存苏铁属内最原始的类群. 5．苏铁属花粉均为远极球形单沟或舟形单沟，外壁表面纹饰为小的凹穴，种间共性明显，只在大小和形状上有微小差别。

木樨科丁香属的系统学研究

丁香属Syringa是木樨科Oleaceae中一个中等大小的属，大多数种类花形美丽，具有很高的园林观赏价值。本文以标本检查为主，结合形态学、孢粉学、细胞学和植物地理学几个方面对丁香属进行了分类研究。 一．形态学：丁香属分类的主要性状为：单叶或复叶、圆锥花序的着生位置、花冠管的长短。这些性状的演化趋势为：单叶--羽状深裂--羽状复叶，圆锥花序由顶芽抽生--圆锥花序由侧芽抽生，长花冠管，雄蕊不伸出花冠管--短花冠管，雄蕊伸出花冠管。 二．孢粉学：本文首次对丁香属的花粉形态作了较为全面而系统的研究。所取材料为各组、系、亚系的代表种。孢粉学的研究表明，本属花粉形态一致。均为近球形，极面观3裂圆形，三（拟）孔沟，沟边缘不加厚，外壁分层明显，外层厚于内层，半覆盖层，粗网状纹饰。扫描电镜观察结果表明，本属花粉的表面纹饰可区分为6种类型：1）．网眼小，网脊细、较直而使网眼呈多边形，网脊下小柱不明显，2).网眼稍大，网脊细、直，网脊下小柱不明显，3),网眼较大，网脊细、稍弯曲，网脊下小柱可见，4）．网眼大，网脊细而弯曲， 网脊下小明显，5).网眼小，网脊细、弯曲而使网眼呈不规则扁长形，6）．网眼较大，网脊粗、直，网脊下小柱不明显。顶生花序系Ser. Villosae (Schneid.) Rehd. 以1型为主，侧生花序系Ser. Syringa从2-4型，羽叶丁香系Ser, Pinnatifolia Rehd,为5型，短花冠管组Sect.Ligustrina Rupr.为6型。其变化规律与形态学上的系统演化关系相—致。 三，细胞学：本文对丁香属部分种进行了染色体数目的观察，初步的结果显示，本属的染色体基数为n=23或24，这两种情况在不同的组、系都存在。本属为异源多倍体起源，由陵花目中染色体基数为n=ll和n=12的祖先类群通过杂交形成，并由于染色体组在减数分裂过程中非整倍性变异，而产生n 2或n=24的变化。 四，分类修订及系统位置和演化趋势： 本文在查看了本所标本馆全部丁香属的标本、考证了约22个种的原始描述以及部分模式标本和模式照片的基础上，对该属分类作下列修订：1．将华丁香Syringa protolaciniata、花叶丁香S．x persica、 裂叶丁香S．x laciniata、阿富汗丁香S．afghanica 四个种从欧丁香亚系中移出，置于羽叶丁香系Ser. Pinnatifolia，2．改欧丁香系Set. Vulgares和巧铃花系Ser. Pubescentes为亚系等级，均置于侧生花序系Ser. Syringa中，3．恢复山丁香Syringa potaninii Schneid.、小叶丁香S．micropylla Diels、关东丁香s．patula (Palibin) Nakai、光萼丁香S．juliana Schneid.、朝鲜丁香S．dilatata Nakai，并作为种的等级，毛萼云南丁香S．yunanensis Franch.f．pubicalyx (Jien ex P.Y. Bai) M.C. Chang仍作变种处理。在此基础上，本文将丁香属分为2组3系2亚系： 组1．长花冠管组Sect.l. Syringa:系1．顶生花序系Ser.1．Villosae(Sch- neid.)Rehd.;系2．侧生花序系Ser.2. Syringa，亚系1．欧丁香亚系Subser.1．Syring，亚系2．巧铃花亚系Pubescentes(Schneid.)Rehd.;系3．羽叶丁香系Ser.3. Pinnatifoliae Rehd. 组2．短花冠管组Sect.2. Ligustrina Rupr. 各分类单元的命名，仍沿用已有的名称。 结合各方面的研究成果，表明丁香属是一个十分自然的类群。在木樨科中，本属与女贞属的关系密切，由女贞属裂果女贞组Sect. Sarcocarpion (Franch.)Mansf.衍生而来。属内演化趋势始为长花冠管组的顶生花序系，而后是侧生花序系、羽叶丁香系，短花冠管组为本属中进化程度较高的类群。 五．植物地理学：丁香属为旧世界温带分布型属，分布区连续。约28种5变种9变型。除2种产于欧洲，1种产于阿富汗、巴基斯坦，1种产于朝鲜，1种产于日本外，其余种类均分布于中国。其中，中国西南地区丁香属的种类、原始类型及其在该地区所占比例均显示是丁香属现代分布中心和起源演化中心，并由此沿三条主线向周围扩散。