Proceedings from the First Biannual Conference on Technological Learning and Thinking: Culture, Design, Sustainability, Human Ingenuity held in Vancouver, BC, Canada, 2010., Not peer reviewed, Conference paper
Dorsal root injury (DRI) disrupts the flow of sensory information to the spinal cord. Although primary afferents do not regenerate to their original targets, spontaneous recovery can, by unknown mechanisms, occur after DRI. Here, we show that brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), but not nerve growth factor or neurotrophin-4, are upregulated in the spinal gray matter after DRI. Because endognous BDNF and NT-3 have well established roles in synaptic and axonal plasticity, we hypothesized that they contributed to spontaneous recovery after DRI. We first developed a model of DRI-induced mechanosensory dysfunction: rat C7/8 DRI produced a deficit in low-threshold cutaneous mechanosensation that spontaneously improved within 10 d but did not recover completely. To determine the effects of endogenous BDNF and NT-3, we administered TrkB-Fc or TrkC-Fc fusion proteins throughout the recovery period. To our surprise, TrkB-Fc stimulated complete recovery of mechanosensation by 6 d after DRI. It also stimulated mechanosensory axon sprouting but prevented deafferentation-induced serotonergic sprouting. TrkC-Fc had no effect on low-threshold mechanosensory behavior or axonal plasticity. There was no mechanosensory improvement with single-bolus TrkB-Fc infusions at 10 d after DRI (despite significantly reducing rhizotomy-induced cold pain), indicating that neuromodulatory effects of BDNF did not underlie mechanosensory recovery. Continuous infusion of the pan-neurotrophin antagonist K252a also stimulated behavioral and anatomical plasticity, indicating that these effects of TrkB-Fc treatment occurred independent of signaling by other neurotrophins. These results illustrate a novel, plasticity-suppressing effect of endogenous TrkB ligands on mechanosensation and mechanosensory primary afferent axons after spinal deafferentation., Peer-reviewed article, Published. Received Oct. 2, 2006; revised March 26, 2007; accepted April 20, 2007.
Proceedings of 4th International Building Physics Conference: 15 June 2009, Istanbul, Turkey.
This is the first of a series of papers to present the results of this major project. In this paper, an overview of the project, its objectives and the theoretical approach to determine the WER are presented. A description of air leakage and R-value test procedures, wall samples construction and the experimental results of two walls and a sample of the analytical results of the same two walls will also be presented. Future papers will summa-rise the experimental and analytical results of the remaining walls, along with the results of the computer modeling of the air leakage and thermal performance of all the walls tested in this project., Conference paper, Published. A version of this document is published in: 4th International Building Physics Conference, Istanbul, Turkey, June 15-18, 2009, pp. 1-8.
This project proposes teaching-learning coupling as students take different roles during the course, from being learners, teachers, and proponents; finally, students take exams in a collaborative manner – initially, their exam is done individually followed by a team consultation period for the exam completion., Not peer reviewed, report
This paper presents a model of environmental regulation in the presence of measurement costs and asymmetric information. Environmental regulation can be viewed as a form of agency problem where the polluting firms may have better information about the true level of their abatement activities than the regulator. If certain aspects of environmental quality are costly to measure, regulators may resort to proxies to infer information about environmental quality. This may allow firms to circumvent the regulatory constraints by maximizing along those margins that are costly to measure. This problem is especially acute when a single firm produces multiple pollutants., Essay, Published.
Essiac, a widely consumed, sparsely tested herbal tea, was evaluated for preparation consistency and antiproliferative effects on prostate cancer cells and xenografts. High performance liquid chromatography (HPLC) was used to compare different lots of Essiac and evaluate extraction consistency by comparing peak areas in concentrated preparations. Repeated analysis of one lot showed < 2% RSD between corresponding peaks. Absolute peak areas varied widely between lots, but similarity in relative size of corresponding peaks was observed. Cytotoxic effects of Essiac were tested in vitro by crystal violet assay and analysis of cell cycle distribution by flow cytometry, but no differences between control and treatment groups was observed. Paclitaxel was used as a positive control in cell cycle analysis and was the only treatment which showed significant effects on cell cycle distribution. Toxicity in nude mice was tested, and efficacy in inhibiting PC-3 xenograft growth. No toxicity or tumour size difference was observed dosing up to 240 mg/kg QD, over 28 days, excepting the positive control group treated with paclitaxel. Ki-67 and PCNA expression was analyzed in treated tumors, but no difference in expression of either marker was observed. These evaluations suggest Essiac has no marked antiproliferative effect on the models tested., Peer-reviewed article, Published.
Proceedings of the 3rd Building Enclosure Science & Technology (BEST3) Conference, Atlanta, USA, April 2-4, 2012. The thermal performance of two innovative pre-fabricated wood-frame wall systems was evaluated in comparison with a conventional 2x6 wood frame wall through one year’s field monitoring on BCIT’s Building Envelope Test Facility. Prefabricated wall system I has 4” Expanded Polystyrene (EPS) infill in the stud cavity with 1” additional EPS added on the interior side of 2x4 wood stud. Prefabricated wall system II has 4” EPS infill in the stud cavity only. The conventional 2x6 wood frame wall has 5-1/2” fiberglass insulation infill in the stud cavity. The effective thermal efficiency of these test walls is evaluated in terms of heat flux, effective in-situ R-values, and temperature distribution. The heat flux measurements show that, in comparison with the conventional 2x6 wood frame wall, prefabricated wall system I with 4” EPS infill in the stud cavity has 5.1% less heat loss and 16% less heat gain and the prefabricated wall system II with 1" extra EPS has 22.9% less heat loss and 37.5% less heat gain. The improvement of thermal efficiency in the prefabricated wall systems is mainly attributed to the significant improvement over the stud areas. Estimated effective R-values over the winter months from December 2008 to March 2009 show that the R-value over the stud area in prefabricated wall system I is improved by 32.7% while the R-value over the cavity area is reduced by 8.7%, resulting in a net improvement of effective wall R-value by 2.9%; and the R-value over the stud area in prefabricated wall system II is improved by 112.3% with only a 2.6% improvement in the R-value over the cavity area, resulting in a net improvement of effective wall R-value by 26.5%. Temperature measurements show that the interior surface temperatures over the stud area in the conventional wall fluctuate much more and are higher during the summer months and lower during the winter months compared to the prefabricated systems, due to the thermal bridging effect of the stud., Conference paper, Published.
This paper originates from a project done for and with the assistance of the Operations Strategy Branch, E Division, Royal Canadian Mounted Police. The aim of this study was to test a technological solution to two traditional limitations of information sharing between criminal justice agencies: data quality and privacy concerns. Entity Analytics Software (EAS) was tested in two studies with North American criminal justice agencies. In the first test, duplicated cases held in a police record system were successfully identified (4.0%) to a greater extent than the traditionally used software program (1.5%). This resulted in a difference of 11,954 cases that otherwise would not have been identified as duplications. In the second test, entity information held separately by police and border officials was shared anonymously between these two organizations. This resulted in 1,827 alerts regarding entities that appeared in both systems; traditionally, this information could not have been shared, given privacy concerns, and neither criminal justice agency would be aware of the relevant information held by the other. Data duplication resulted in an additional 1,041 alerts, which highlights the need to use technological solutions to improve data quality prior to and during information sharing. While only one potential technological solution (EAS) was tested and organizations must consider the potential expense associated with implementing such technology, the implications resulting from both studies for improved awareness and greater efficiency support and facilitate information sharing between criminal justice organizations., Research paper, Published.
Proceedings of 2012 IEEE Symposium on Computational Intelligence in Bioinformatics and Computational Biology (CIBCB) on 9-12 May 2012 in San Diego, CA, USA. We use in silico evolution to study the generation of gene regulatory structures. A particular area of interest in evolutionary development (evo-devo) is the correspondence between gene regulatory sequences on the DNA (cis-regulatory modules, CRMs) and the spatial expression of the genes. We use computation to investigate the incorporation of new CRMs into the genome. Simulations allow us to characterize different cases of CRM to spatial pattern correspondence. Many of these cases are seen in biological examples; our simulations indicate relative advantages of the different scenarios. We find that, in the absence of specific constraints on the CRM-pattern correspondence, CRMs controlling multiple spatial domains tend to evolve very quickly. Genes constrained to a one-to-one CRM-pattern domain correspondence evolve more slowly. Of these, systems in which pattern domains appear in a particular order in evolution, as in insect segmentation mechanisms, take the longest time in in silico evolutionary searches. For biological cases of this type, it is likely that other selective advantages outweigh the time costs., Conference paper, Published.
The co-evolution of species with their genomic parasites (transposons) is thought to be one of the primary ways of rewiring gene regulatory networks (GRNs). We develop a framework for conducting evolutionary computations (EC) using the transposon mechanism. We find that the selective pressure of transposons can speed evolutionary searches for solutions and lead to outgrowth of GRNs (through co-option of new genes to acquire insensitivity to the attacking transposons). We test the approach by finding GRNs which can solve a fundamental problem in developmental biology: how GRNs in early embryo development can robustly read maternal signaling gradients, despite continued attacks on the genome by transposons. We observed co-evolutionary oscillations in the abundance of particular GRNs and their transposons, reminiscent of predator-prey or host-parasite dynamics., Peer-reviewed article, Published.