Absolute energy curves from late B-type supergiants

Energy curves were determined for six late B and early A type supergiants using IUE data and other ultraviolet and ground based photometry. Effective temperatures and angular diameters are presented as well as estimates of the outflow velocity of the wind. All six stars show a strong Balmer continuum in emission; the Ia supergiants also show an infrared excess which reaches into the visible range. Evidence is found for the presence of a warm mantle as well as for wind from the Ia stars

Hyaluronan Is Inversely Correlated with the Expression of CD44 in the Dermal Condensation of the Embryonic Hair Follicle

Previously, we have shown that CD44 (the hyaluronan receptor) was involved in the degradation of hyaluronan. In the present study, we examined the distribution of CD44 and hyaluronan in the skin of embryonic and mature mice. During embryonic development, CD44 was prominently expressed by the condensed mesenchymal cells involved in the Formation of the hair follicles, but was absent from the surrounding interstitial cells. The cells of the dermal condensation expressed CD44 throughout the development of the hair follicle; however, once the hair follicle reached maturity, the mesenchymal cells of the dermal papilla no longer expressed this molecule. In contrast to the above, the distribution of hyaluronan was reversed from that of CD44. Hyaluronan was widespread throughout the embryonic dermis, but was conspicuously absent from the regions of the dermal condensation. This arrangement persisted through the development of the hair follicle; however, in the mature hair follicle, hyaluronan reappeared in the dermal papilla. Thus in the embryonic dermis, the expression of CD44 and hyaluronan were complementary to each other. However, in the adult skin, only minor changes were detected in the levels of CD44 and hyaluronan associated with the cells of the dermal condensation during the hair cycle. When organ cultures of embryonic mouse skin were treated with Streptomyces hyaluronidase, the interstitial mesenchymal cells became compacted, indicating that the removal of hyaluronan leads to the condensation of these cells. The results of this study are Consistent with the hypothesis that the expression of CD44 by the inductive mesenchymal cells allows them to degrade hyaluronan in a localized region, leading to formation and maintenance of the dermal condensation

O stars and Wolf-Rayet stars

Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented

Spatial patterning of liver progenitor cell differentiation mediated by cell contractility and notch signaling

Liver progenitor cell differentiation and bile duct formation are driven by spatially-dependent and temporally-sequenced cell–cell and cell–factor interactions coordinated by several biochemical signaling pathways, namely Notch and TGFβ. The regionalization of biliary differentiation and morphogenesis near the portal region of the liver has suggested that spatially segregated microenvironmental signals govern this process. Our recent work utilizing biomaterial substrates of defined stiffness suggests that mechanical cues play a previously-unrecognized role in liver progenitor differentiation. Here, we used a cell microarray platform that enables the simultaneous analysis of these biochemical and biomechanical microenvironmental cues to define the mechanisms of action and functional overlap of these pathways. We used bipotential mouse embryonic liver (BMEL) progenitor cells cultured by standard techniques (M. Weiss and H. Strick-Marchand, Institut Pasteur). To present Notch ligand to cells, we printed Fc-chimeric recombinant DLL4 on a polyacrylamide hydrogel substrate together with collagen I and Protein A/G. We integrated this cell microarray platform with traction force microscopy (TFM) by adding fiducial beads to the polyacrylamide hydrogel and imaging bead displacement before and after cell dissociation. Please click Additional Files below to see the full abstract

Substrate stiffness and VE-cadherin mechano-transduction coordinate to regulate endothelial monolayer integrity.

The vascular endothelium is subject to diverse mechanical cues that regulate vascular endothelial barrier function. In addition to rigidity sensing through integrin adhesions, mechanical perturbations such as changes in fluid shear stress can also activate force transduction signals at intercellular junctions. This study investigated how extracellular matrix rigidity and intercellular force transduction, activated by vascular endothelial cadherin, coordinate to regulate the integrity of endothelial monolayers. Studies used complementary mechanical measurements of endothelial monolayers grown on patterned substrates of variable stiffness. Specifically perturbing VE-cadherin receptors activated intercellular force transduction signals that increased integrin-dependent cell contractility and disrupted cell-cell and cell-matrix adhesions. Further investigations of the impact of substrate rigidity on force transduction signaling demonstrated how cells integrate extracellular mechanics cues and intercellular force transduction signals, to regulate endothelial integrity and global tissue mechanics. VE-cadherin specific signaling increased focal adhesion remodeling and cell contractility, while sustaining the overall mechanical equilibrium at the mesoscale. Conversely, increased substrate rigidity exacerbates the disruptive effects of intercellular force transduction signals, by increasing heterogeneity in monolayer stress distributions. The results provide new insights into how substrate stiffness and intercellular force transduction coordinate to regulate endothelial monolayer integrity

Attitudes of advanced Australian medical oncology trainees to rural practice

Aim: To identify the views of medical oncology trainees regarding rural training posts and rural practice overall, and to identify factors that may improve recruitment. Methods: A questionnaire was posted to all advanced oncology trainees in Australia in June 2006. The trainees were questioned on the perceived advantages and disadvantages of rural practice, their experience during previous rural rotations and potential incentives and barriers in recruiting trainees and specialist oncologists to regional and rural centers. Results: There was a 60% response rate. Of all participants 58% had considered rural practice. Those with a rural family background were more likely to have considered rural practice. Attitudes based on responses to listed disadvantages and advantages of rural practice were heterogenous. Lifestyle factors seemed to be of particular importance. Although there were perceived deficiencies in opportunities for professional education in rural oncology rotations, 94% felt their rotation had been a positive experience overall and 62% were more likely to consider a rural career following their rural rotation. Improving locum cover for leave was seen as a potential incentive by 97% trainees. Conclusion: Despite positive attitudes towards rural practice, many barriers exist preventing recruitment of medical oncology trainees to rural areas, in particular lifestyle factors that are difficult to modify. Factors that can be improved include improving access to clinical trials, enabling access to locum cover. Educational opportunities for current rural trainees need to be improved. Further study into potential incentives to enhance rural recruitment is required

Sources and legitimacy of financial liberalization

AbstractThis article seeks to clarify how we understand domestic and international sources of globalization and specifically how we explain financial liberalization across countries. The article also develops our understanding of the underlying legitimacy of financial liberalization. We debate e.g. Abiad and Mody (2005) and others who have found political factors to have little impact on financial openness. Using the same data undergirding such conclusions we argue, in contrast, that even a slight broadening of the political variables employed in the model and much closer attention to “input” and “output” aspects of the political legitimacy of financial liberalization over time reveal a more central role for politics in shaping liberalization. Input legitimacy involves the representation of stakeholders in initial and ongoing decisions to liberalize, while “output” legitimacy concerns liberalization's distributional consequences and management thereof over time. Several empirical measures of domestic-national and international political factors plausibly influence such aspects of legitimacy and are found to play a significant role in shaping liberalization, suggesting legitimation politics to be more important to financial openness than existing studies have typically acknowledged

The Origin of Nonradiative Heating/momentum in Hot Stars

The origin of nonradiative heating and momentum in the atmospheres of stars is studied. The similarities and differences between what occurs in the hot stars and what occurs in cool stars are emphasized. Key points in the theory are reviewed. Areas requiring new study are indicated

On Some General Lacunary Interpolation Problems

AbstractThe object of this paper is to give a unified and complete treatment of these related cases of lacunary interpolation whose special cases can be found scattered in the literature. We consider only the case when the nodes are the zeros ofπn(x) whose derivative is −n(n−1)Pn−1(x), the Legendre polynomial of degreen−1. We find the fundamental polynomials and give the convergence results