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Special Mode (special + mode)
Selected AbstractsCleavage-like cell division and explosive increase in cell number of neonatal gonocytesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2004Yasuhiro Sakai Based on previous conventional quantitative observations of rat testes, it was proposed that large numbers of gonocytes degenerate after birth and this notion was widely accepted. However, many studies show that neonatal gonocytes display high levels of mitotic activity. In order to resolve the apparent contradiction of increased mitotic activity in gonocytes despite a decrease in their numbers at the neonate stage, quantitative analysis using a marker of suitably higher resolution is required. It has been shown that the vasa protein could be used as a marker of germ cells. In this study, quantitative changes in gonocytes were re-examined using a germ-cell-specific marker in order to delineate more clearly the process of development from gonocytes to spermatogonia after birth. The vasa -positive cells, which correspond to gonocytes and spermatogonia, increased exponentially after birth. This observation suggests that all gonocyte divide actively after birth and do not degenerate as previously believed. Surprisingly, the cell volume of gonocytes decreased during their division. The largest population size was 2000,4000 µ3 at day 2, 1000,2000 µ3 at day 4 and 500,1000 µ3 at day 6. This finding suggests that gonocytes divide in a similar way to cleavage, which can be considered a special mode of fertilized eggs. Judging from the growth of seminiferous tubules and the degree of volume reduction, 60% of the contribution rate is estimated to be due to ordinal cell growth, and 40% due to volume reduction as in cleavage of a fertilized egg. This unique cleavage-like division may contribute to the supply of large numbers of spermatogonia. [source] Equality and Constitutional Indeterminacy An Interpretative Perspective on the European Economic ConstitutionEUROPEAN LAW JOURNAL, Issue 2 2001Alexander Somek It is claimed that European supranationalism represents an unprecedented mode of political association whose point is to maintain what is good about nationality and the nation state by stripping the latter of its adverse effects. In this article, this claim is submitted to a test by examining how different ways of conceiving of anti-discrimination in the context of intra-Community trading law give rise to two different conceptions of the European economic constitution. While the first one is married to the ideal of behavioural anti-discrimination,that is, of affording protection against discriminatory acts by Member States,whose application would seemingly leave the nation state in its place, the other one takes a system of nation states as something that in and of itself engenders systematically discriminatory effects on international trade. According to the latter, effective anti-discrimination presupposes overcoming such a system altogether. Both conceptions of the economic constitution are manifest in Community law, and at first glance it appears as if adherence to the first one would be consonant with supranationality as a special mode of political association. However, owing to internal predicaments arising from the application of the equality principle (understood as a principle protecting against discrimination), the difference between both conceptions cannot be upheld in practice. Since the first conception is constantly undermined by the second in the course of its application, it remains uncertain, at least in this context, whether or not the European nation state is left in place by the European Economic Constitution. [source] When machines get stuck,obstructed RNA polymerase II: displacement, degradation or suicideBIOESSAYS, Issue 9 2002Vincent van den Boom The severe hereditary progeroid disorder Cockayne syndrome is a consequence of a defective transcription-coupled repair (TCR) pathway. This special mode of DNA repair aids a RNA polymerase that is stalled by a DNA lesion in the template and ensures efficient DNA repair to permit resumption of transcription and prevent cell death. Although some key players in TCR, such as the Cockayne syndrome A (CSA) and B (CSB) proteins have been identified, the exact molecular mechanism still remains illusive. A recent report provides new unexpected insights into TCR in yeast.1 The identification and characterisation of a novel protein co-purifying with the yeast homologue of CSB (Rad26) imposes reassessment of our current understanding of TCR in yeast. What about humans? BioEssays 24:780,784, 2002. © 2002 Wiley Periodicals, Inc. [source] Mechanisms and Kinetics of the Hydrothermal Oxidation of Bulk Titanium Silicon CarbideJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2010Haibin Zhang Hydrothermal oxidation of bulk Ti3SiC2 in continuous water flow was studied at 500°,700°C under a hydrostatic pressure of 35 MPa. The oxidation was weak at 500°,600°C and accelerated at 700°C due to the formation of cracks in oxides. The kinetics obeyed a linear time-law. Due to the high solubility of silica in hydrothermal water, the resulting oxide layers only consisted of titanium oxides and carbon. Besides general oxidation, two special modes are very likely present in current experiments: (1) preferential hydrothermal oxidation of lattice planes perpendicular to the c -axis inducing cleavage of grains and (2) uneven hydrothermal oxidation related to the occurrence of TiC and SiC impurity inclusions. Nonetheless the resistance against hydrothermal oxidation is remarkably high up to 700°C. [source] | ||||||||||