Fiduciary Liability Under the Federal Priority Statutes

Myriad aspects of commercial interaction between the federal government and individuals may be affected by the near-ancient sections 3466 and 3467 of the Revised Statutes which subject a fiduciary of an insolvent estate to personal liability for failure to grant priority to specified governmental claims. In an attempt to guide the practitioner through the maze of contingencies presented by these provisions, the author outlines considerations relevant to an assessment of the applicability and effect of the statutory priorities

The risk of transmission of a viral haemorrhagic fever infection in a United Kingdom laboratory

No abstract available

Optimisation of growth conditions for ovine airway epithelial cell differentiation at an air-liquid interface

Respiratory tract infections are of significant concern in the agriculture industry. There is a requirement for the development of well-characterised in vitro epithelial cell culture models in order to dissect the diverse molecular interactions occurring at the host-pathogen interface in airway epithelia. We have analysed key factors that influence growth and differentiation of ovine tracheal epithelial cells in an air-liquid interface (ALI) culture system. Cellular differentiation was assessed at 21 days post-ALI, a time-point which we have previously shown to be sufficient for differentiation in standard growth conditions. We identified a dose-dependent response to epidermal growth factor (EGF) in terms of both epithelial thickening and ciliation levels. Maximal ciliation levels were observed with 25 ng ml-1 EGF. We identified a strict requirement for retinoic acid (RA) in epithelial differentiation as RA exclusion resulted in the formation of a stratified squamous epithelium, devoid of cilia. The pore-density of the growth substrate also had an influence on differentiation as high pore-density inserts yielded higher levels of ciliation and more uniform cell layers than low pore-density inserts. Differentiation was also improved by culturing the cells in an atmosphere of sub-ambient oxygen concentration. We compared two submerged growth media and observed differences in the rate of proliferation/expansion, barrier formation and also in terminal differentiation. Taken together, these results indicate important differences between the response of ovine tracheal epithelial cells and other previously described airway epithelial models, to a variety of environmental conditions. These data also indicate that the phenotype of ovine tracheal epithelial cells can be tailored in vitro by precise modulation of growth conditions, thereby yielding a customisable, potential infection model

Effects of Flow Path Factors in the Permeability of Natural and Man-made Granular Soils Using the Kozeny-Carman Equation

The research presented in this paper serves to observe how the flow path factors relate to the void ratio, the effective diameter of a soil particle, and the permeability of a given sample assuming the behavior is consistent across natural and artificial soils. The basis of the comparison is the derived Kozeny-Carman Equation for permeability with focus on the factors Cs and Cl where Cs represents the shape of the flow path and Cl represents the length of the flow path that a single water molecule must travel through a soil sample. Permeameter tests were conducted for six types of material including three natural sands and two man-made samples to compare data. Man-made or unnatural samples included stainless steel pins and ceramic spheres. Four other natural sands were tested at both 50% and 90% relative density to compare data. Natural sands included C33 sand, Quartz sand, Fine Ottawa sand and Coarse Ottawa sand. It was observed that while the permeability of the samples was impacted by the geometry of the flow paths, as shown in the flow path factors CsCl, as well as the void ratios, it appears that the effective diameter Ds has a larger impact on permeability

Temporal dynamics of ovine airway epithelial cell differentiation at an air-liquid interface

The respiratory tract and lungs are subject to diverse pathologies with wide-ranging implications for both human and animal welfare. The development and detailed characterization of cell culture models for studying such forms of disease is of critical importance. In recent years the use of air-liquid interface (ALI)-cultured airway epithelial cells has increased markedly, as this method of culture results in the formation of a highly representative, organotypic in vitro model system. In this study we have expanded on previous knowledge of differentiated ovine tracheal epithelial cells by analysing the progression of differentiation over an extensive time course at an ALI. We observed a pseudo-stratified epithelium with ciliation and a concurrent increase in cell layer thickness from 9 days post-ALI with ciliation approaching a maximum level at day 24. A similar pattern was observed with respect to mucus production with intensely stained PAS-positive cells appearing at day 12. Ultrastructural analysis by SEM confirmed the presence of both ciliated cells and mucus globules on the epithelial surface within this time-frame. Trans-epithelial electrical resistance (TEER) peaked at 1049 Ω × cm2 as the cell layer became confluent, followed by a subsequent reduction as differentiation proceeded and stabilization at ~200 Ω × cm2. Importantly, little deterioration or de-differentiation was observed over the 45 day time-course indicating that the model is suitable for long-term experiments