Nanoparticle transport in saturated porous medium using magnetic resonance imaging

Transport study of nanoparticle (NP) through matrix flow dominated aquifer sand and soils have significant influence in natural systems. To quantify the transport behaviour, magnetic resonance imaging (MRI) was used to image the iron oxide based nanoparticle, Molday ION (carboxyl terminated) through saturated sandstone rock core. T2-weighted images were acquired and the changes in image intensity were calibrated to get a quantitative concentration profiles at various time intervals. These profiles were evaluated through CXTFIT transport model to estimate the transport parameters. These parameters are estimated at various points along the length of the column while classical breakthrough curve analysis cannot provide these details. NP–surface interactions were investigated using DLVO (Derjaguin–Landau–Verwey–Overbeek) theory. The dispersion coefficients (2.55–1.21 × 10−7 m2/s) were found to be decrease with distance, deposition rate constant k (6.70–9.13 × 10−4 (1/s)) and fast deposition rate constant kfast (4.32–8.79 × 10−2 (1/s)) were found to be increase with distance. These parameter variations over length will have a scaling up impact in developing transport models for environmental remediation and risk assessment schemes

Effective Storytelling in Business School Ethics Curriculum

Narrative, or storytelling, is a tool increasingly used by business to effectively portray complex business issues in a manner which is engaging, comprehensive and easily comprehended. Instructors in a business school setting can also make use of narrative as a tool to engage their students in the complexities of business. The use of narrative places theoretical concepts in the context of actual (or hypothetical) business situations in a way that emphasizes the importance and the difficulties inherent in effective business decision-making. Where business decisions involve ethical issues, narrative is particularly effective because it illustrates the personal and emotional implications these decisions have to the decision-maker, the decision-maker’s organization and the organization’s broad array of stakeholders. In the context of the delivery of ethics curriculum in business schools, storytelling can particularly engaging because of the emotional responses from students that these stories generate

Interactions and Tradeoffs Between Cell Recruitment, Proliferation, and Differentiation Affect CNS Regeneration

AbstractRegeneration of central nervous system (CNS) lesions requires movement of progenitor cells and production of their differentiated progeny. Although damage to the CNS clearly promotes these two processes, the interplay between these complex events and how it affects a response remains elusive. Here, we use spatial stochastic modeling to show that tradeoffs arise between production and recruitment during regeneration. Proper spatial control of cell cycle timing can mitigate these tradeoffs, maximizing recruitment, improving infiltration into the lesion, and reducing wasteful production outside of it. Feedback regulation of cell lineage dynamics alone however leads to spatial defects in cell recruitment, suggesting a novel, to our knowledge, hypothesis for the aggregation of cells to the periphery of a lesion in multiple sclerosis. Interestingly, stronger chemotaxis does not correct this aggregation and instead, substantial random cell motions near the site of the lesion are required to improve CNS regeneration