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Preliminary results from field experimental study of rain load and penetration into wood-frame wall systems at window sill defects
14th Canadian Conference on Building Science and Technology, Toronto, Canada, October 29th-30th, 2014. A field study is presented here on the investigation of the correlation between wind-driven rain (WDR) as the driving force and the relative proportions of water penetration at intended defects (openings) located at the interface of windows and exterior walls. In this field study, eight full-scale exterior-wall panels of vinyl siding and stucco claddings were built and installed on a field testing station, which is subjected to British Columbia’s west coast climate rain. This paper focuses on the preliminary results from one of the stucco wall panels with a discontinuity in the sealant around the perimeters of the windows. The water passing through this defect was collected and measured. The instantaneous and automatic water collection measurements were synchronized to the data gathered by a nearby weather station on wind-driven rain intensity, wind speed and direction. In addition, rain gauges on exterior of walls collected the wind-driven rain against each façade of the test station. Compared to previous computer simulations and laboratory experimental studies on rain penetration through exterior walls, this study was conducted under more realistic conditions. The panels were subjected to real wind-driven rain events. Also collectively, the experiment took into account rain that splashed off the wall façade upon impact and the rain water around the defect location due to run-off. The study is ongoing. However, when complete, the results from this study will be useful for fine-tuning the principal moisture load that is applied in hygrothermal performance assessment and design of exterior wall systems., Conference paper, Published.
Program Comprehension: Identifying Learning Trajectories for Novice Programmers
This working group asserts that Program Comprehension (PC) plays a critical part in the writing process. For example, this abstract is written from a basic draft that we have edited and revised until it clearly presents our idea. Similarly, a program is written in an incremental manner, with each step being tested, debugged and extended until the program achieves its goal. Novice programmers should develop their program comprehension as they learn to code, so that they are able to read and reason about code while they are writing it. To foster such competencies our group has identified two main goals: (1) to collect and define learning activities that explicitly cover key components of program comprehension and (2) to define possible learning trajectories that will guide teachers using those learning activities in their CS0/CS1 or K-12 courses. We plan to achieve these goals as follows: Step 1 Review the current state of research and development by analyzing literature on classroom activities that improve program comprehension. Step 2 Concurrently, survey lecturers at various institutions on their use of workshop activities to foster PC. Step 3 Use the outputs from both activities to define and conceptualize what is meant by PC in the context of novice programmers. Step 4 Catalog learning activities with regard to their prerequisites, intended learning outcomes and additional special characteristics. Step 5 Catalog learning activities with regard to their prerequisites, intended learning outcomes and additional special characteristics. Step 6 Develop a map of learning activities and thereby also models of probable learning trajectories., Not peer reviewed, Conference proceedings
Program comprehension: identifying learning trajectories for novice programmers
This working group asserts that Program Comprehension (PC) plays a critical part in the writing process. For example, this abstract is written from a basic draft that we have edited and revised until it clearly presents our idea. Similarly, a program is written in an incremental manner, with each step being tested, debugged and extended until the program achieves its goal. Novice programmers should develop their program comprehension as they learn to code, so that they are able to read and reason about code while they are writing it. To foster such competencies our group has identified two main goals: (1) to collect and define learning activities that explicitly cover key components of program comprehension and (2) to define possible learning trajectories that will guide teachers using those learning activities in their CS0/CS1 or K-12 courses. We plan to achieve these goals as follows: Step 1 Review the current state of research and development by analyzing literature on classroom activities that improve program comprehension. Step 2 Concurrently, survey lecturers at various institutions on their use of workshop activities to foster PC. Step 3 Use the outputs from both activities to define and conceptualize what is meant by PC in the context of novice programmers. Step 4 Catalog learning activities with regard to their prerequisites, intended learning outcomes and additional special characteristics. Step 5 Catalog learning activities with regard to their prerequisites, intended learning outcomes and additional special characteristics. Step 6 Develop a map of learning activities and thereby also models of probable learning trajectories., Not peer reviewed, Conference proceedings
Proteomic analysis of the effects of aged garlic extract and its FruArg component on lipopolysaccharide-induced neuroinflammatory response in microglial cells
Aged garlic extract (AGE) is widely used as a dietary supplement, and is claimed to promote human health through anti-oxidant/anti-inflammatory activities with hypolipidemic, antiplatelet and neuroprotective effects. Prior studies of AGE have mainly focused on its organosulfur compounds, with little attention paid to its carbohydrate derivatives, such as N-α-(1-deoxy-D-fructos-1-yl)-L-arginine (FruArg). The goal of this study is to investigate actions of AGE and FruArg on antioxidative and neuroinflammatory responses in lipopolysaccharide (LPS)-activated murine BV-2 microglial cells using a proteomic approach. Our data show that both AGE and FruArg can significantly inhibit LPS-induced nitric oxide (NO) production in BV-2 cells. Quantitative proteomic analysis by combining two dimensional differential in-gel electrophoresis (2D-DIGE) with mass spectrometry revealed that expressions of 26 proteins were significantly altered upon LPS exposure, while levels of 20 and 21 proteins exhibited significant changes in response to AGE and FruArg treatments, respectively, in LPS-stimulated BV-2 cells. Notably, approximate 78% of the proteins responding to AGE and FruArg treatments are in common, suggesting that FruArg is a major active component of AGE. MULTICOM-PDCN and Ingenuity Pathway Analyses indicate that the proteins differentially affected by treatment with AGE and FruArg are involved in inflammatory responses and the Nrf2-mediated oxidative stress response. Collectively, these results suggest that AGE and FruArg attenuate neuroinflammatory responses and promote resilience in LPS-activated BV-2 cells by suppressing NO production and by regulating expression of multiple protein targets associated with oxidative stress., Peer-reviewed article, Published. Received: May 16, 2014; Accepted: October 24, 2014; Published: November 24, 2014.
Protracted myelin clearance hinders central primary afferent regeneration following dorsal rhizotomy and delayed neurotrophin-3 treatment
Regeneration within or into the CNS is thwarted by glial inhibition at the site of a spinal cord injury and at the dorsal root entry zone (DREZ), respectively. At the DREZ, injured axons and their distal targets are separated by degenerating myelin and an astrocytic glia limitans. The different glial barriers to regeneration following dorsal rhizotomy are temporally and spatially distinct. The more peripheral astrocytic barrier develops first, and is surmountable by neurotrophin-3 (NT-3) treatment; the more central myelin-derived barrier, which prevents dorsal horn re-innervation by NT-3-treated axons, becomes significant only after the onset of myelin degeneration. Here we test the hypothesis that in the presence of NT-3, axonal regeneration is hindered by myelin degeneration products. To do so, we used the Long Evans Shaker (LES) rat, in which oligodendrocytes do not make CNS myelin, but do produce myelin-derived inhibitory proteins. We show that delaying NT-3 treatment for 1 week in normal (LE) rats, while allowing axonal penetration of the glia limitans and growth within degenerating myelin, results in misdirected regeneration with axons curling around presumptive degenerating myelin ovoids within the CNS compartment of the dorsal root. In contrast, delaying NT-3 treatment in LES rats resulted in straighter, centrally-directed regenerating axons. These results indicate that regeneration may be best optimized through a combination of neurotrophin treatment plus complete clearance of myelin debris., Peer-reviewed article, Published. Received 3 June 2006, Revised 8 September 2006, Accepted 8 September 2006, Available online 22 November 2006.
Purification and characterization of a selective growth regulator for human myelopoietic progenitor cells
A monoclonal antibody, named CAMAL-1, was raised previously in our laboratory to a common antigen of acute myeloid leukemia (CAMAL), and was shown to be highly specific in its recognition of cells from patients with acute (AML) or chronic (CML) myelogenous leukemia. CAMAL was also reported to be prognostic of disease, in that patients whose numbers of CAMAL-1 reactive cells were high, or rose over time, had poorer prognoses and shorter survival times than patients whose CAMAL values were low or decreased. This correlation between CAMAL and disease prognosis led to the discovery that CAMAL-1immunoaffinity-purified leukemic cellular lysates contained a selective growth inhibitory activity for normal myeloid progenitor cells, since the growth of CML progenitors was not inhibited. The work described in this thesis focused primarily on the purification and characterization of the myelopoietic activity present in the CAMAL preparations, and its relationship to the leukemic marker (CAMAL). Initial purifications involved CAMAL-1immunoaffinity chromatography of leukemic cellular lysates, followed by FPLC molecular size fractionation and/or preparative SDS-PAGE. The myelopoietic activity was located within a30-35 kDa molecular weight fraction (P30), and the P30 fraction was consistently found to be selective in its inhibition of normal myeloid progenitors, since the growth of CML progenitors was not inhibited but was, in fact, stimulated. Antibodies were raised to P30 and used in the subsequent purification and characterization of the myelopoietic activity. Amino acid sequence analysis of the N-terminus and P30 tryptic peptides strongly suggested that P30 belonged to the serine protease family of enzymes, and the results obtained from protease assays indicated thatP30 preparations did possess enzyme activity. Prior to the completion of P30 molecular cloning experiments, however, the cDNA sequence for azurocidin/CAP37 was reported, and its predicted amino acid sequence was found to be identical to those obtained from the P30 protein samples. Azurocidin is a proteolytically inactive serine protease homologue, normally present in neutrophilic granules. Purifiedazurocidin did not possess inhibitory activity in normal progenitor cell assays; therefore, in order to isolate the biologic activity from azurocidin and other potentially contaminating proteins, P30 preparations were fractionated by reverse phase HPLC. The rpHPLC profiles were found to be similar to those reported for neutrophilic granules; however, the myelopoietica ctivity was obtained in a single rpHPLC fraction that aligned with the front portion of the azurocidin protein peak. Two dimensional isoelectric focusing/SDS-PAGE analysis of the biologically active rpHPLC fraction confirmed that it contained azurocidin, and no additional protein species were detected. Only the earlier eluting azurocidin rpHPLC fraction mediated the myelopoietic activity, and this fraction was also enriched in the higher molecular weight isoforms of azurocidin. Therefore, it appeared that a variably glycosylated isoform of azurocidin was mediating the biologic effects on myeloid progenitor cells, and because azurocidin obtained from normal neutrophils did not possess the myelopoietic activity, we speculate that the bioactive isoform of azurocidin is present in relatively higher amounts and/or is uniquely synthesized by leukemic cells., Thesis, Published.
Quantification of pyrrolizidine alkaloids in North American plants and honey by LC-MS
Pyrrolizidine alkaloids (PAs) are a class of naturally occurring compounds produced by many flowering plants around the World. Their presence as contaminants in food systems has become a significant concern in recent years. For example, PAs are often found as contaminants in honey through pollen transfer. A validated method was developed for the quantification of four pyrrolizidine alkaloids and one pyrrolizidine alkaloidN-oxide in plants and honey grown and produced in British Columbia. The method was optimised for extraction efficiency from the plant materials and then subjected to a single-laboratory validation to assess repeatability, accuracy, selectivity, LOD, LOQ and method linearity. The PA content in plants ranged from1.0 to 307.8 µg/g with repeatability precision between 3.8 and 20.8% RSD. HorRat values were within acceptable limits and ranged from 0.62 to 1.63 for plant material and 0.56–1.82 for honey samples. Method accuracy was determined through spike studies with recoveries ranging from 84.6 to 108.2% from the raw material negative control and from 82.1–106.0 % for the pyrrolizidine alkaloids in corn syrup. Based on the findings in this single-laboratory validation, this method is suitable for the quantitation of lycopsamine, senecionine, senecionineN-oxide, heliosupine and echimidine in common comfrey (Symphytum officinale), tansy ragwort (Senecio jacobaea), blueweed (Echium vulgare) and hound’s tongue (Cynoglossum officinale)and for PA quantitation in honey and found that PA contaminants were present at low levels in BC honey., Peer-reviewed article, Published. Received 4 June 2015; accepted 20 September 2015.
Quantifying the effects of on-the-fly changes of seating configuration on the stability of a manual wheelchair
Proceedings of the 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), in Seogwipo, South Korea, 11-15 July 2017. In general, manual wheelchairs are designed with a fixed frame, which is not optimal for every situation. Adjustable on the fly seating allow users to rapidly adapt their wheelchair configuration to suit different tasks. These changes move the center of gravity (CoG) of the system, altering the wheelchair stability and maneuverability. To assess these changes, a computer simulation of a manual wheelchair was created with adjustable seat, backrest, rear axle position and user position, and validated with experimental testing. The stability of the wheelchair was most affected by the position of the rear axle, but adjustments to the backrest and seat angles also result in stability improvements that could be used when wheeling in the community. These findings describe the most influential parameters for wheelchair stability and maneuverability, as well as provide quantitative guidelines for the use of manual wheelchairs with on the fly adjustable seats., Conference paper, Published.
A quantitative study of cotyledon positioning in conifer development
The number of cotyledons in angiosperm monocots and dicots is tightly constrained. But in the gymnosperm Pinaceae (pine family), which includes many of the conifers, cotyledon number ( nc) can vary widely, commonly from 2 to 12. Conifer cotyledons form in whorled rings on a domed embryo geometry. We measured the diameter of embryos and counted the cotyledons to determine the radial positioning of the whorl and the circumferential spacing between cotyledons. Results were similar between Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco), Sitka spruce ( Picea sitchensis (L.) H.Karst .), and larch ( Larix × leptoeuropaea, synonymous with L. × marschlinsii Coaz), indicating a common mechanism for cotyledon positioning in conifers. Disrupting transport of the growth regulator auxin (with 1- N-naphthylphthalamic acid (NPA)) led to cup-shaped embryos, indicating that whorl (ring) formation is separable from cotyledon patterning within the ring. NPA inhibits cotyledon outgrowth, but not the spacing (distance) between cotyledons. The NPA effect is direct; it does not operate indirectly on embryo size. These results support a hierarchical model for cotyledon positioning in conifers, in which a first stage (not requiring auxin transport) sets the whorl position, constraining the second stage (which requires auxin transport) to form cotyledons within this whorl. Similarly, recent studies in Arabidopsis have shown that different components of complex developmental patterns can have different transport properties; this aspect of patterning may be shared across plants., Peer-reviewed article, Published. Received 27 November 2015. Accepted 8 April 2016.
Quasi real-time ZIP load modeling for Conservation Voltage Reduction of smart distribution networks using disaggregated AMI data
This paper aims to investigate quasi real-time ZIP load models for new Smart Grid-based Volt-VAR Optimization (VVO) techniques. As recent VVO solutions are able to perform in quasi real-time using Advanced Metering Infrastructure (AMI) data, more accurate load modeling could give distribution network operators and/or planners more precise Conservation Voltage Regulation (CVR) and energy saving values at each operating time stage. Furthermore, more accurate load modeling of each quasi real-time stage could improve VVO efficiency. As type, amount and operating time of each residential appliance varies throughout a day, this paper aims to discover ZIP load model of each quasi real-time stage separately through disaggregated data (i.e. decomposing residential load consumption into home appliance consumptions). This paper shows that the energy conservation achieved by CVR operation through presented quasi real-time ZIP load modeling could lead AMI-based VVO solutions to higher level of accuracy and data resolution compared with conventional techniques. Therefore, this paper primarily introduces a new quasi real-time AMI-based VVO engine. Then, it investigates ZIP load model of each quasi real-time stage through statistical data to conserve energy consumption. To check the authenticity and the applicability of presented model in a whole system, 33-node distribution feeder is employed., Published. Received 16 March 2015, Revised 14 May 2015, Accepted 3 June 2015, Available online 2 July 2015.
Ranking functions for belief change
Proceedings of the 6th International Conference on Agents and Artificial Intelligence in Angers, France, 2014. In this paper, we explore the use of ranking functions in reasoning about belief change. It is well-known that the semantics of belief revision can be defined either through total pre-orders or through ranking functions over states. While both approaches have similar expressive power with respect to single-shot belief revision, we argue that ranking functions provide distinct advantages at both the theoretical level and the practical level, particularly when actions are introduced. We demonstrate that belief revision induces a natural algebra over ranking functions, which treats belief states and observations in the same manner. When we introduce belief progression due to actions, we show that many natural domains can be easily represented with suitable ranking functions. Our formal framework uses ranking functions to represent belief revision and belief progression in a uniform manner; we demonstrate the power of our approach through formal results, as well as a series of natural problems in commonsense reasoning., Conference paper, Published.
Raphe-spinal neurons display an age-dependent differential capacity for neurite outgrowth compared to other brainstem-spinal populations
Functional regeneration of brainstem–spinal pathways occurs in the developing chick when the spinal cord is severed prior to embryonic day (E) 13. Functional spinal cord regeneration is not observed in animals injured after E13. This developmental transition from a permissive to a restrictive repair period may be due to the formation of an extrinsic inhibitory environment preventing axonal growth, and/or an intrinsic inability of mature neurons to regenerate. Here, we investigated the capacity of specific populations of brainstem–spinal projection neurons to regrow neurites in vitro from young (E8) versus mature (E17) brainstem explants. A crystal of carbocyanine dye (DiI) was implanted in ovo into the E5 cervical spinal cord to retrogradely label brainstem–spinal projection neurons. Three or 12 days later, discrete regions of the brainstem containing DiI-labeled neurons were dissected to produce explant cultures grown in serum-free media on laminin substrates. The subsequent redistribution of DiI into regenerating processes permitted the study of in vitro neurite outgrowth from identified brainstem–spinal neurons. When explanted on E8, i.e., an age when brainstem–spinal neurons are normally elongating through the spinal cord and are capable of in vivo functional regeneration, robust neurite outgrowth was observed from all brainstem populations, including rubro-, reticulo-, vestibulo-, and raphe–spinal neurons. In contrast, when explanted on E17, robust neurite outgrowth was seen only from raphe-spinal neurons. Neurite outgrowth from raphe-spinal neurons was 5-hydroxy-tryptamine immunoreactive. This study demonstrates that in growth factor-free environments with permissive growth substrates, neurite outgrowth from brainstem–spinal neurons is dependent on both neuronal age and phenotype., Peer-reviewed article, Published. Received 22 February 2000; Accepted 25 May 2000; Available online 25 May 2002.

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