激光光散射及荧光光谱法研究金属离子对牛磺胆酸钠胶团性质的影响

采用激光光散射的方法，研究了Ｃａ￣（２＋）、Ｌａ￣（３＋）、Ｅｕ￣（３＋）存在下，ＮａＴＣ胶团及其与胆固醇、卵磷脂形成的混合胶团平均流体力学半径变化，发现金属离子能使胶团长大，并对胶团的结构及对胆固醇的增溶性有影响。以芘为荧光探针，研究了Ｃａ￣（２＋）、Ｌａ￣（３＋）离子对胶团内部微极性的影响，及通过Ｅｕ￣（３＋）的荧光光谱表征其配位场特征，证明金属离子与胆盐胶团间相互作用发生在胶团的表面。     

Hemolymph coagulation in Macropipus puber (L.) Crustacea Decapoda. Respective roles of hemolymph and plasma]

The process of coagulation of the hemolymph in Macropipus puber (L.) Crustacea Decapod depends on one or several plasmatic factors and on a thermo-labile cellular factor which does not seem to be specific. The existence of these factors has been demonstrated.     

Pluralism, Economic Rhetoric, and Common Property

This paper presents a preliminary discussion of different ideological traditions of economic thought. The philosophical foundations and methodological implications of neoclassical, institutional, and neo-Marxist political economy are discussed by building upon the "system of systems methodologies" as a starting "modelling space". Drawing upon postmodern discourses, this typology is used as a rhetorical tool to assist with clear exposition. Two general applications are discussed, firstly a conceptual application to some contemporary perspectives of common property, and secondly a practical application to questions of investment in stormwater and wastewater. It is concluded that previously unrecognised common ground can emerge from attempts to communicate across traditional organisational and ideological divides.     

Implications of the polymorphism of HLA-G on its function,regulation, evolution and disease association

The HLA-G gene displays several peculiarities that are distinct from those of classical HLA class I genes. The unique structure of the HLA-G molecule permits a restricted peptide presentation and allows the modulation of the cells of the immune system. Although polymorphic sites may potentially influence all biological functions of HLA-G, those present at the promoter and 3′ untranslated regions have been particularly studied in experimental and pathological conditions. The relatively low polymorphism observed in the MHC-G coding region both in humans and apes may represent a strong selective pressure for invariance, whereas, in regulatory regions several lines of evidence support the role of balancing selection. Since HLA-G has immunomodulatory properties, the understanding of gene regulation and the role of polymorphic sites on gene function may permit an individualized approach for the future use of HLA-G for therapeutic purposes.     

Ovulated oocytes in adult mice derive from non-circulating germ cells

Decades of research in reproductive biology have led to the generally accepted belief that in female mammals, all surviving germ cells enter meiosis at the end of fetal development and as a result, the postnatal ovary harbours a limited supply of oocytes that cannot be replenished or regenerated if lost to injury or disease. However, recent reports have challenged this view, suggesting instead that oocyte production is maintained through continual seeding of the ovary by circulating, bone-marrow-derived germ cells. To test directly the physiological relevance of circulating cells for female fertility, we established transplantation and parabiotic mouse models to assess the capacity of circulating bone marrow cells to generate ovulated oocytes, both in the steady state and after induced damage. Our studies showed no evidence that bone marrow cells, or any other normally circulating cells, contribute to the formation of mature, ovulated oocytes. Instead, cells that travelled to the ovary through the bloodstream exhibited properties characteristic of committed blood leukocytes.     

MARSIS radar sounder evidence of buried basins in the northern lowlands of Mars

A hemispheric dichotomy on Mars is marked by the sharp contrast between the sparsely cratered northern lowland plains and the heavily cratered southern highlands. Mechanisms proposed to remove ancient crust or form younger lowland crust include one or more giant impacts, subcrustal transport by mantle convection, the generation of thinner crust by plate tectonics, and mantle overturn following solidification of an early magma ocean. The age of the northern lowland crust is a significant constraint on these models. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument on the European Space Agency's Mars Express spacecraft is providing new constraints on the martian subsurface. Here we show evidence of buried impact basins ranging in diameter from about 130 km to 470 km found over approximately 14 per cent of the northern lowlands. The number of detected buried basins >200 km in diameter indicates that the lowland crust is ancient, dating back to the Early Noachian epoch. This crater density is a lower limit because of the likelihood that not all buried basins in the area surveyed by MARSIS have been detected. An Early Noachian age for the lowland crust has been previously suggested on the basis of a large number of quasi-circular topographic depressions interpreted to be evidence of buried basins. Only a few of these depressions in the area surveyed by MARSIS, however, correlate with the detected subsurface echoes. On the basis of the MARSIS data, we conclude that the northern lowland crust is at least as old as the oldest exposed highland crust. This suggests that the crustal dichotomy formed early in the geologic evolution of Mars.