Dynamics of amino acid metabolism of primary human liver cells in 3D bioreactors

The kinetics of 18 amino acids, ammonia (NH3) and urea (UREA) in 18 liver cell bioreactor runs were analyzed and simulated by a two-compartment model consisting of a system of 42 differential equations. The model parameters, most of them representing enzymatic activities, were identified and their values discussed with respect to the different liver cell bioreactor performance levels. The nitrogen balance based model was used as a tool to quantify the variability of runs and to describe different kinetic patterns of the amino acid metabolism, in particular with respect to glutamate (GLU) and aspartate (ASP)

The Geomechanics of CO2 Storage in Deep Sedimentary Formations

This paper provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stress-strain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deployments, mainly at the In Salah CO2 storage project in Algeria, are also integrated into the review. The In Salah project, with its injection into a relatively thin, low-permeability sandstone is an excellent analogue to the saline aquifers that might be used for large scale GCS in parts of Northwest Europe, the U.S. Midwest, and China. Some of the lessons learned at In Salah related to geomechanics are discussed, including how monitoring of geomechanical responses is used for detecting subsurface geomechanical changes and tracking fluid movements, and how such monitoring and geomechanical analyses have led to preventative changes in the injection parameters. Recently, the importance of geomechanics has become more widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO{sub 2} repository (as well as how it could impact the public perception of GCS). As described in the paper, to date, no notable seismic event has been reported from any of the current CO{sub 2} storage projects, although some unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large power plants will require injection at a much larger scale. For such largescale injections, a staged, learn-as-you-go approach is recommended, involving a gradual increase of injection rates combined with continuous monitoring of geomechanical changes, as well as siting beneath a multiple layered overburden for multiple flow barrier protection, should an unexpected deep fault reactivation occur

Emergence of Shared Mental Models During Distributed Teamwork: Integration of Distributed Cognition Traces

Team decision-making becomes more complex when problem specifications and availability of resources change over time. Time constraints may also amplify complexity. Ad hoc team response to this type of change can be studied over time by analyzing distributed cognitive traces and emergence of resource coordination response patterns during the team decision process. Knowledge of team work style patterns gained through such analysis provides criteria for design of adaptive collaborative work systems and development of more effective use patterns. 1 Motivation for the Study Research efforts have focused variously on individually held abstract concepts becoming shared (Cannon-Bowers & Salas, 2001; Langan-Fox, Code, Langfield-Smith, 2000; Levesque, Wilson, & Wholey, 2001) and distributed cognition as an approach to group problem solving (Zhang, 1998). A framework has been suggested for use of distributed cognition as a way to describe interaction (Wright, Fields, & Harrison, 2000). However, I know of no other work attempting to demonstrate, as is the case here, how ad hoc coordination of resources, supervised by a team’s emergent shared mental model, is facilitated by synthesis of emergent distributed cognitive traces. The post-interaction residue left throughout a work or learning environment is a set of cognitive fragments. A transcript of the interaction that occurred over a period of time makes up a set of traces. Traces, in the form of digital artifacts, are footprints that define the path of interaction and resource coordination taken by a team. The emergence of patterns can be tracked over time as teams structure a decision model in response to changing requirements, complexity, time constraints, and availability of resources. The objective of this paper is to demonstrate how distributed cognitive traces stored in environmental artifacts are joined through discourse to form sufficient shared cognition to negotiate production of a satisfactory decision model.