Profiling Mechanisms of Alkane Hydroxylase Activity In Vivo Using the Diagnostic Substrate Norcarane

SummaryMechanistically informative chemical probes are used to characterize the activity of functional alkane hydroxylases in whole cells. Norcarane is a substrate used to reveal the lifetime of radical intermediates formed during alkane oxidation. Results from oxidations of this probe with organisms that contain the two most prevalent medium-chain-length alkane-oxidizing metalloenzymes, alkane ω-monooxygenase (AlkB) and cytochrome P450 (CYP), are reported. The results—radical lifetimes of 1–7 ns for AlkB and less than 100 ps for CYP—indicate that these two classes of enzymes are mechanistically distinguishable and that whole-cell mechanistic assays can identify the active hydroxylase. The oxidation of norcarane by several recently isolated strains (Hydrocarboniphaga effusa AP103, rJ4, and rJ5, whose alkane-oxidizing enzymes have not yet been identified) is also reported. Radical lifetimes of 1–3 ns are observed, consistent with these organisms containing an AlkB-like enzyme and inconsistent with their employing a CYP-like enzyme for growth on hydrocarbons

Virtual Study Abroad and Exchange Studio

The digital design studio has an area of application where conventional media are incapable of being used, collaboration in learning, design and dialogue with people in places other than where one lives. This distinctive opportunity has lead the authors to explore a form of design brief and virtual design studio (VDS) format not well addressed in the literature. Instead of sharing the same design brief, students in this alternative format design a project in the other studentsi city and do not collaborate on the same design. Collaboration with other students takes the form of teaching each other about the city and culture served by the design. The authors discovered these studios produce a focus on site context that serves our pedagogical objectives-a blend of architectural, landscape architectural and urban design knowledge. Their students use a range of commercial CAD and computer supported collaborative work (CSCW) software common to that used in many VDS experiments reported on in the literature. However, this conventional use of technology is contrasted with a second distinctive characteristic of these studios, the use of custom software tools specifically designed to support synchronous and asynchronous three-dimensional model exchange and linked attribute knowledge. The paper analyzes some of the virtual design studio (VDS) work between the Swiss Federal Institute of Technology, the University of Toronto, and the University of Melbourne. The authors articulate a framework of VDS dimensions that structures their teaching and research

Virtual study abroad and exchange studio

The digital design studio has an area of application where conventional media are incapable of being used, collaboration in learning, design and dialogue with people in places other than where one lives. This distinctive opportunity has lead the authors to explore a form of design brief and virtual design studio (VDS) format not well addressed in the literature. Instead of sharing the same design brief, students in this alternative format design a project in the other students'city and do not collaborate on the same design. Collaboration with other students takes the form of teaching each other about the city and culture served by the design. The authors discovered these studios produce a focus on site context that serves our pedagogical objectives - a blend of architectural, landscape architectural and urban design knowledge. Their students use a range of commercial CAD and computer supported collaborative work (CSCW) software common to that used in many VDS experiments reported on in the literature. However, this conventional use of technology is contrasted with a second distinctive characteristic of these studios, the use of custom software tools specifically designed to support synchronous and asynchronous three-dimensional model exchange and linked attribute knowledge. The paper analyzes some of the virtual design studio (VDS) work between the Swiss Federal Institute of Technology, the University of Toronto, and the University of Melbourne. The authors articulate a framework of VDS dimensions that structures their teaching and research

Computing the Composition of Ethanol-Water Mixtures Based on Experimental Density and Temperature Measurements

Two correlations were developed to calculate the composition of binary ethanol-water solutions from experimental temperature and density inputs. The first correlation is based on a Redlich-Kister (R-K) expansion and computes mixture composition within an average accuracy of ±0.45 wt.%. The R-K model is a non-linear function of composition and therefore requires the use of an iterative solving tool. A polynomial correlation was additionally developed which utilizes a direct solving method, and computes ethanol composition over a range of 0–100 wt.% [283.15–313.15 K] with an accuracy better than ±0.37 wt.%. The polynomial model is particularly advantageous as it can be tailored to specific composition ranges for increased accuracy. Both correlations are intended to provide a method for monitoring ethanol concentration within a chemical process in real time without off-line sample analysis, allowing for precise in-situ system control and optimization

Filtering of impulse noise in digital signals using logical transform

Median filters excel at removing impulse noise from digital signals, with high accuracy and quick running-times. However, they have limitations if the resulting signals are to be used for feature recognition purposes, as they often remove crucial details and add unwanted noise. In this paper, an algorithm for digital filtering using the logical transform is proposed. This method is able to achieve mean-squared-error results similar to median type filters while maintaining image details. Variations of the algorithm allow for greater noise reduction, but at the cost of increased computation