BCIT Citations Collection | BCIT Institutional Repository

BCIT Citations Collection

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Collection of published works from BCIT researchers, faculty, and instructors.

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A logical approach to promoting trust over knowledge to trust over action
Proceedings of 2016 14th Annual Conference on Privacy, Security and Trust (PST) in Auckland, New Zealand 12-14 Dec. 2016. We discuss two related forms of trust. One form of trust is related to the perceived knowledge of other agents; we accept the information that another agent provides if we believe they have sufficient expertise in a particular domain. The second form is related to action; we trust another agent to act on our behalf if we believe they will choose acceptable actions. In this paper, we explore the relationship between these two forms of trust. In particular, we use an existing model of trust to demonstrate how trust over knowledge can determine when trust over actions is appropriate. We take a formal approach to this problem, using logic-based tools for representing and reasoning about actions and beliefs to characterize trust over action. While our primary aim is to develop a formal methodology that permits trust over actions to be defined in terms of trust over knowledge, we also consider applications that are both practical and speculative. On the practical side, we consider how our methods can be used to reason about trusted third parties in communication protocols. On the speculative side, we suggest that models of trust have a role to play in the development of ethical decision-making agents., Conference paper, Published.
Long-term effects of spinal cord injury on sexual function in men
Study Design: Secure, web-based survey. Objectives: Elicit specific information about sexual function from men with spinal cord injuries (SCI). Setting: World-wide web. Methods: Individuals 18 years or older living with SCI obtained a pass-code to enter a secure website and then answered survey questions. Results: The presence of genital sensation was positively correlated with the ability to feel a build up of sexual tension in the body during sexual stimulation and in the feeling that mental arousal translates to the genitals as physical sensation. There was an inverse relationship between developing new areas of arousal above the level of lesion and not having sensation or movement below the lesion. A positive relationship existed between the occurrence of spasticity during sexual activity and erectile ability. Roughly 60% of the subjects had tried some type of erection enhancing method. Only 48% had successfully achieved ejaculation postinjury and the most commonly used methods were hand stimulation, sexual intercourse, and vibrostimulation. The most commonly cited reasons for trying to ejaculate were for pleasure and for sexual intimacy. Less than half reported having experienced orgasm postinjury and this was influenced by the length of time postinjury and sacral sparing. Conclusion: SCI not only impairs male erectile function and ejaculatory ability, but also alters sexual arousal in a manner suggestive of neuroplasticity. More research needs to be pursued in a manner encompassing all aspects of sexual function., Peer-reviewed article, Published.
Low consistency refining of oxalic acid pretreated wood shavings
The objective of this study was to evaluate the potential use of wood shavings as a raw material for the low consistency (LC) refining at the primary refining stage to significantly reduce electrical energy consumption. It was possible to produce wood shavings with longer fibre length than wood chips. Oxalic acid, followed by alkaline peroxide, was applied to both wood shavings and wood chips before LC refining. LC refined wood shavings were found to be a low energy raw material. The refining energy was reduced by about 33% using wood shavings compared to wood chips at a given freeness, and oxalic acid pretreatment of wood shavings further reduced the refining energy by approximately 57%. Tensile strength and brightness of LC refined wood shavings was found to be higher than high-consistency refined wood chips. Oxalic acid pretreatment further improved the tensile strength of LC refined wood shavings, but not the brightness. This study demonstrates the potential to develop a novel mechanical pulping process that produces high tensile, high brightness pulp with half the electrical energy consumption. Both wood chips and wood shavings produced in the laboratory were used as a feeding material in HC and LC refining processes, respectively. Fibre length of wood shavings was longer than that of wood chips. As refining proceeded, fibre length of LC refined wood shavings was reduced more than that of HC refined wood chips. Oxalic acid pretreatment further reduced the fibre length of LC refined wood shavings. A great advantage of using wood shavings was found in reducing refining energy over wood chips. LC refined wood shavings reduced the refining energy about 33% compared to HC refined wood chips at a given freeness. Oxalic acid followed by alkaline peroxide pretreatment of wood shavings further reduced refining energy by approximately 57%., Peer-reviewed article, Published.
Low voltage distribution substation integration in smart Microgrid
Proceeding of IEEE 8th Conference on PowerElectronics, Jeju Island, South Korea, June 2011. A strategy is proposed to introduce a limited set of monitoring and control functions into a legacy low voltage distribution substation, and as such integrate it into a larger command and control architecture of a smart Microgrid. The focus of the work shall be on the retrofit strategy of some of the key components for measurement, monitoring, protection and control systems of the substation. Also Volt/VAR optimization of the feeder shall be considered as a part of the design. The article discusses the structure of the substation under study, followed by the actual design of IEC 61850 subsystems for the substation. A simulation model of the pilot project and its results is also included in the paper., Conference paper, Published.
Lycopene differentially induces quiescence and apoptosis in androgen-responsive and -independent prostate cancer cell lines
Background & aims: Lycopene has been credited with a number of health benefits including a decrease in prostate cancer risk. Our study investigates the molecular mechanism underlying anti-cancer activity of lycopene-based products in androgen-responsive (LNCaP) and androgen-independent (PC3) cells. Methods: The effect of lycopene-based agents on prostate cancer growth and survival were examined using proliferation assays, bromodeoxyuridine incorporation and flow cytometric analysis of cellular DNA content. Biochemical effects of lycopene treatment were investigated by immunoblotting for changes in the absolute levels and phosphorylation states of cell cycle regulatory and signalling proteins. Results: LNCaP and PC3 cells treated with the lycopene-based agents undergo mitotic arrest, accumulating in G0/G1 phase. Immunoblot screening indicated that lycopene's antiproliferative effects are likely achieved through a block in G1/S transition mediated by decreased levels of cyclins D1 and E and cyclin dependent kinase 4 and suppressed Retinoblastoma phosphorylation. These responses correlated with decreased insulin-like growth factor-I receptor expression and activation, increased insulin-like growth factor binding protein 2 expression and decreased AKT activation. Exposure to lycopene at doses as low as 10nM for 48h induced a profound apoptotic response in LNCaP cells. In contrast PC3 cells were resistant to apoptosis at doses up to 1μM. Conclusions: Lycopene exposure can suppress phosphatidylinositol 3-kinase-dependent proliferative and survival signalling in androgen-responsive LNCaP and androgen-independent PC3 cells suggesting that the molecular mechanisms for the cytostatic and cytotoxic actions of lycopene involve induction of G0/G1 cell cycle arrest. This study supports further examination of lycopene as a potential agent for both the prevention and treatment of prostate cancer., Peer-reviewed article, Published.
Lz-0 × Berkeley
This study describes the generation and test of a genetic resource suited to identify determinants of cell biological traits in plants. The use of quantitative trait loci (QTL) mapping for a better genetic understanding of cell biological traits is still at an early stage, even for biotechnologically important cell properties, such as the dimensions of fiber cells. A common strategy, the mapping of QTLs in recombinant inbred line (RIL) populations, is limited by the fact that the existing RIL populations exploit only a small fraction of the existing natural variation. Here, we report the mapping of QTLs impacting on the length of fiber cells in Arabidopsis inflorescence stems in a newly generated RIL population derived from a cross between the accessions Berkeley and the little known Lz-0. Through inbreeding of individual F(2) plants, a total of 159 new F8 lines were produced and genotyped with a set of 49 single nucleotide polymorphism markers. The population was successfully used not only for the mapping of three QTLs controlling fiber length, but also to map five QTL controlling flowering time under short and long-day conditions. Our study demonstrates the usefulness of this new genetic resource by mapping in it QTLs underlying a poorly explored cellular trait as well as an already better explored regulatory pathway. The new RIL population and an online platform for the continuous supplementation of genetic markers will be generally available to substantially broaden the genetic diversity through which loci with impact on plant quantitative traits can be identified., Peer-reviewed article, Published. Received: 1 October 2012, Accepted: 25 January 2014; Published online: 15 February 2014.
Magneto-optical trap loading rate dependence on trap depth and vapor density
We study the dependence of the particle loading rate of a rubidium vapor cell magneto-optic trap (MOT). Using a trap depth determination of the MOT that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state, we experimentally determine the MOT escape velocity and show that the loading rate scales with escape velocity to the fourth power, or, equivalently, with the square of the trap depth. We also demonstrate that the loading rate is directly proportional to the background rubidium density. We thus experimentally confirm the loading rate model used in the literature since the invention of the MOT. In addition to confirming this long-standing conjecture, we show that the loading rate dependence can be used to reliably infer the trap depth and to tune the relative depth of a MOT (i.e., capture and escape velocities) when the background density is held fixed. The measurements have allowed an experimental determination of the relationship between capture and escape velocities in our MOTs of 𝑣𝑐=1.29(0.12)𝑣𝑒., Peer-reviewed article, Published.
Maintaining apical dominance in the fern gametophyte
A kinetic model is developed for cell differentiation in the fern gametophyte to test hypotheses on the role of spatially patterned plasmodesmata networks in development. Of particular interest is the establishment and maintenance of apical cell type in a single cell, with concurrent suppression of this character in all other cells (apical dominance). Steps towards understanding apical cell localization in geometrically simple gametophytes may shed light on the establishment and maintenance of apical meristems in higher plants. The model, based on the plasmodesmata maps of Tilney and colleagues and involving kinetics for a requisite minimum of two morphogens, successfully produces the apical/non‐apical cell differentiation patterns of normal development, and redifferentiation due to cell isolation, in six stages from 0–30 d of development. Our results indicate that increasing apical cell plasmodesmata number, as development progresses, is not required for effective transport across apical cell walls in maintaining apical dominance., Peer-reviewed article, Published. Received: 3 August 2001; Returned for revision: 12 November 2001; Accepted: 17 December 2001.
Making the body plan
We quantify fluctuations in protein expression for three of the segmentation genes in the fruit fly, Drosophila melanogaster. These proteins are representative members of the first three levels of a signalling hierarchy which determines the segmented body plan: maternal (Bicoid protein); gap (Hunchback protein); and pair-rule (Even-skipped protein). We quantify both inter-embryo and inter-nucleus (within a single embryo) variability in expression, especially with respect to positional specification by concentration gradient reading. Errors are quantified both early and late in cleavage cycle 14, during which the protein patterns develop, to study the dynamics of error transmission. We find that Bicoid displays very large positional errors, while expression of the downstream genes, Hunchback and Even-skipped, displays far more precise positioning. This is evidence that the pattern formation of the downstream proteins is at least partially independent of maternal signal, i. e. evidence against simple concentration gradient reading. We also find that fractional errors in concentration increase during cleavage cycle 14., Peer-reviewed article, Published. Received 30 September 2002; Accepted 12 December 2002; Published 16 December 2002.
A mammalian artificial chromosome engineering system (ACE System) applicable to biopharmaceutical protein production, transgenesis and gene-based cell therapy
Mammalian artificial chromosomes (MACs) provide a means to introduce large payloads of genetic information into the cell in an autonomously replicating, non-integrating format. Unique among MACs, the mammalian satellite DNA-based Artificial Chromosome Expression (ACE) can be reproducibly generated de novo in cell lines of different species and readily purified from the host cells' chromosomes. Purified mammalian ACEs can then be re-introduced into a variety of recipient cell lines where they have been stably maintained for extended periods in the absence of selective pressure. In order to extend the utility of ACEs, we have established the ACE System, a versatile and flexible platform for the reliable engineering of ACEs. The ACE System includes a Platform ACE, containing >50 recombination acceptor sites, that can carry single or multiple copies of genes of interest using specially designed targeting vectors (ATV) and a site-specific integrase (ACE Integrase). Using this approach, specific loading of one or two gene targets has been achieved in LMTK− and CHO cells. The use of the ACE System for biological engineering of eukaryotic cells, including mammalian cells, with applications in biopharmaceutical production, transgenesis and gene-based cell therapy is discussed., Peer-reviewed article, Publsihed.
The marihuana indoor production calculator
The clandestine nature of illicit indoor marihuana production makes is difficult to measure the true extent of marihuana cultivation in a given policing jurisdiction. As a result, law enforcement must rely on estimations in order to understand the scale of the problem in terms of the number of growing operations, the number of growers, or the monetary value of the industry. This article describes an online estimation tool that was developed to aid law enforcement in the estimation of the annual production, domestic sale, exportation, and total value of marihuana produced in commercial growing operations within a given jurisdiction., Research article, Published.
Measurement of anomalous dispersion in molecular iodine vapour by a simple interferometric method
The index of refraction of iodine vapour was measured in regions of anomalous dispersion. These measurements were made using a Michelson interferometer illuminated by a tunable dye laser, and encompass 30 GHz regions centered near 17 408.3 and 17 565.1 cm−1. These regions contained several rovibrational lines of the transition, and at a vapour pressure of 0.28 Torr (1 Torr = 133.3 Pa) the index of refraction near these lines was found to vary by a few parts in 107., Peer-reviewed article, Published.
Measuring gene expression noise in early drosophila embryos
Proceedings of the International Conference on Computational Science, ICCS 2012. In recent years the analysis of noise in gene expression has widely attracted the attention of experimentalists and theoreticians. Experimentally, the approaches based on in vivo fluorescent reporters in single cells appear to be straightforward and effective tools for bacteria and yeast. However, transferring these approaches to multicellular organisms presents many methodological problems. Here we describe our approach to measure between-nucleus variability (noise) in the primary morphogenetic gradient of Bicoid (Bcd) in the precellular blastoderm stage of fruit fly (Drosophila) embryos. The approach is based on the comparison of results for fixed immunostained embryos with observations of live embryos carrying fluorescent Bcd (Bcd-GFP). We measure the noise using two-dimensional Singular Spectrum Analysis (2D SSA). We have found that the nucleus-to-nucleus noise in Bcd intensity, both for live (Bcd-GFP) and for fixed immunstained embryos, tends to be signal-independent. In addition, the character of the noise is sensitive to the nuclear masking technique used to extract quantitative intensities. Further, the method of decomposing the raw quantitative expression data into a signal (expression surface) and residual noise affects the character of the residual noise. We find that careful masking of confocal images and use of appropriate computational tools to decompose raw expression data into trend and noise makes it possible to extract and study the biological noise of gene expression., Conference paper, Published.
Mechanical properties of low-strength concrete blocks simulating construction in developing countries
Proceedings of the 12th North American Masonry Conference in Boulder, Colorado, May 17-20th, 2015. It is believed that one of the causes for unacceptably high death toll in the 2010 Haiti earthquake was due to use of low-strength hollow concrete blocks for masonry construction. After the earthquake, a team of BCIT faculty and students started to work on developing a low-cost nondestructive testing device for strength evaluation of concrete blocks which could be used in Haiti and other countries. The concept is based on the relationship between the compressive strength and the corresponding resonant frequency determined when a block is subjected to a mild impact. A simple block mould procured from Haiti was used to manufacture units with varying mix proportions typical of low-to medium-strength concrete blocks. In total, more than 70 concrete blocks and companion cylinders were made using13 different mix proportions to determine the compressive strength and other mechanical properties., Conference paper, Published.
Mid-embryo patterning and precision in Drosophila segmentation
In early development, genes are expressed in spatial patterns which later define cellular identities and tissue locations. The mechanisms of such pattern formation have been studied extensively in early Drosophila (fruit fly) embryos. The gap gene hunchback (hb) is one of the earliest genes to be expressed in anterior-posterior (AP) body segmentation. As a transcriptional regulator for a number of downstream genes, the spatial precision of hb expression can have significant effects in the development of the body plan. To investigate the factors contributing to hb precision, we used fine spatial and temporal resolution data to develop a quantitative model for the regulation of hb expression in the mid-embryo. In particular, modelling hb pattern refinement in mid nuclear cleavage cycle 14 (NC14) reveals some of the regulatory contributions of simultaneously-expressed gap genes. Matching the model to recent data from wild-type (WT) embryos and mutants of the gap gene Krüppel (Kr) indicates that a mid-embryo Hb concentration peak important in thoracic development (at parasegment 4, PS4) is regulated in a dual manner by Kr, with low Kr concentration activating hb and high Kr concentration repressing hb. The processes of gene expression (transcription, translation, transport) are intrinsically random. We used stochastic simulations to characterize the noise generated in hb expression. We find that Kr regulation can limit the positional variability of the Hb mid-embryo border. This has been recently corroborated in experimental comparisons of WT and Kr- mutant embryos. Further, Kr regulation can decrease uncertainty in mid-embryo hb expression (i.e. contribute to a smooth Hb boundary) and decrease between-copy transcriptional variability within nuclei. Since many tissue boundaries are first established by interactions between neighbouring gene expression domains, these properties of Hb-Kr dynamics to diminish the effects of intrinsic expression noise may represent a general mechanism contributing to robustness in early development., Peer-reviewed article, Published. Received: December 5, 2014; Accepted: December 15, 2014; Published: March 20, 2015.
Mitigating agricultural greenhouse gas emissions
Agriculture contributes significantly to anthropogenic greenhouse gases (GHGs), with estimates of agriculture's contribution ranging from 10% to 25% of total global GHG emissions per year. The science regarding mitigating (reducing and removing) GHGs through agriculture is conflicting and inconclusive. However, the severity and urgency of climate change and its potential effects on food security demonstrate that we must include mitigation within food system planning frameworks. In British Columbia, Canada, the provincial government has established significant GHG reduction targets for its agencies, and has called on local governments to reduce their carbon footprints through a charter and incentive, as well as through growth management legislation. At the same time, local governments, are giving increased attention to development of local/regional agri-food systems. However, GHG mitigation efforts do not yet seem to factor into local agri-food system discussions. Although frameworks for reporting agriculture GHGs exist, local government measurement of agriculture mitigation is hampered by a lack of agriculture GHG inventories, limited data availability, and the inherent variability in agriculture emissions and removals due to the dynamic nature of farm ecosystems. With the goal of informing local governments and food system planners on the importance of agriculture GHG mitigation, this paper (1) reviews the science of GHGs, (2) describes sources of agriculture GHG emissions and illustrates potential mitigation practices, (3) discusses the variability of agriculture mitigation science, (4) highlights the importance of agriculture GHG inventories, and (5) emphasizes the necessity for local agriculture mitigation strategies., Peer-reviewed article, Published. Submitted 18 April 2011 ; Revised 4 July 2011 and 1 August 2011 ; Accepted 2 September 2011 ; Published online 20 March 2012.

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