Physics of Neutron Star Crusts

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.Comment: 182 pages, published version available at <http://www.livingreviews.org/lrr-2008-10

Pulmonary surfactant expression analysis-Role of cell-cell interactions and 3-D tissue-like architecture

Surfactant production is important in maintaining alveolar function both in vivo and in vitro, but surfactant expression is the primary property lost by alveolar Type II Pneumocytes in culture and its maintenance is a functional requirement. To develop a functional tissue-like model, the in vivo cell-cell interactions and three dimensional architecture has to be reproduced. To this end, 3D button-shaped synthetic gelatin vinyl acetate (GeVAc) co-polymer scaffold was seeded with different types of lung cells. Functionality of the construct was studied under both static and dynamic conditions. The construct was characterized by Environmental Scanning Electron and fluorescent microscopy, and functionality of the system was analyzed by studying mRNA modulations of all four surfactant genes A, B, C, and D by real time-PCR and varying culture conditions. The scaffold supports alveolar cell adhesion and maintenance of cuboidal morphology, and the alveolar-specific property of surfactant synthesis, which would otherwise be rapidly lost in culture. This is a novel 3D system that expresses all 4 surfactants for a culture duration of 3 weeks

Effect of tobacco extract on surfactant synthesis and its reversal by retinoic acid—role of cell–cell interactions in vitro

Tobacco induces oxidative stress in the alveolar epithelium and causes its damage. Retinoic acid (RA) has a cardinal role in alveolar cell growth, differentiation, and maturation. The aim of the study was to investigate the role of cell-cell interactions and whether RA could reverse the effect of tobacco extract on epithelial function as expressed by surfactant synthesis. For this, an in vitro model, which provides multiple cell type interactions, as seen in vivo, was used. We had used the major lung cell types, alveolar epithelial and mesenchymal cells represented by the cell lines A549 (human lung adenocarcinoma cell line), and human fetal lung fibroblast-1 (HFL-1) for developing the monoculture and co-culture systems and studied the effect of tobacco extract and retinoic acid. The effect of tobacco and retinoic acid both singly and in combination on proliferation and surfactant synthesis was analyzed. Retinoic acid induced proliferation and upregulated surfactant synthesis in monocultures and co-cultures. Tobacco extract at 100 mu g/ml concentration decreased A549 proliferation and upregulated surfactant protein mRNA expression. In co-cultures treated with tobacco extract (100 mu g/ml), retinoic acid (1 mu M), regulated cell proliferation, and surfactant protein mRNA expression vis-A -vis the monoculture system. This clearly points to the fact that cell-cell interactions modulate the effect of additives or stimulants and help in assessing the in vivo combinatorial responses in vitro and that the retinoic acid effect is regenerative

The domains of intellectual capital: an integrative discourse across perspectives

This chapter explores the domains of intellectual capital (IC) more commonly known as human, organisation and social capital. This theoretical analysis draws together these three disciplinary domains through an integrative discourse in terms of leveraging accumulative resources, connecting complementary themes and distinguishing between interdependent cognitions and behaviours. It seeks to answer scholarly concerns that the IC construct is vague and misleading, resulting in erroneous and generalised relationships. The chapter adopts a theoretical lens and explores complementary discourses of the relationships between human capital (HC), human capital resources (HCR), organisational capital and social capital (SC). For HC and HCR, the discussions build on the resource-based view and the micro-foundations approaches in the strategy literature, where recent research has explored linkages between HCR and competitive advantage. The SC literature is outlined and the discourse between internal SC and external SC is spelled out. The discourses between the domains suggest that through a process of emergence, firms can develop dynamic capabilities that enable them to achieve competitive advantage in factor markets. In light of this, the chapter builds on and complements other recent research that has extended scholarly concerns about the lack of an integrative framework by which the IC linkages and variables can be developed and tested