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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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.
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.
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.
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.
Modeling the evolution of gene regulatory networks for spatial patterning in embryo development
A central question in evolutionary biology concerns the transition between discrete numbers of units (e.g. vertebrate digits, arthropod segments). How do particular numbers of units, robust and characteristic for one species, evolve into another number for another species? Intermediate phases with a diversity of forms have long been theorized, but these leave little fossil or genomic data. We use evolutionary computations (EC) of a gene regulatory network (GRN) model to investigate how embryonic development is altered to create new forms. The trajectories are epochal and non-smooth, in accord with both the observed stability of species and the evolvability between forms., Peer-reviewed article, Published.
Moisture response of sheathing board in conventional and rain-screen wall systems with shiplap cladding
Building enclosures are subjected to a random climatic loading on the exterior surface and a relatively stable indoor condition on the interior. These loadings result in a transport of heat, air, and moisture across the building enclosure. In this paper, the drying and wetting of sheathing board in two exterior walls, more specifically 2×6 in.2 wood-frame conventional (no strapping between sheathing membrane and cladding) and a rain-screen wall system (with vertical strapping), are investigated through an experimental field study. The experiment is carried out at British Columbia Institute of Technology field exposure test facility, where the test walls are exposed to the coastal climate (Vancouver weather) on the exterior and controlled indoor temperature and relative humidity conditions in the interior. The field experimental results indicate significant moisture accumulation on the exterior sheathing boards (plywood) during the Winter period. During the 9-month monitoring period from March 13 to Dec. 6, 2009, the plywood underwent a process of drying and wetting. In both the conventional and rain-screen wall systems, the plywood dried to a comparable moisture level during the Summer before the wetting process started. For the wall systems considered in this study, the plywood in the rain-screen wall has a tendency of faster drying and wetting in the Spring and Fall seasons, respectively, in comparison to the plywood in the conventional wall, which is attributed to the presence of an air gap in the rain-screen wall between the sheathing membrane and the cladding. A similar trend is observed during the monitoring period from December 7 to June 15, 2010., Peer-reviewed article, Published. Manuscript received January 14, 2010; accepted for publication August 14, 2010; published online October 2010.
Molecular targets for therapeutic intervention after spinal cord injury
In an effort to develop therapies for promoting neurological recovery after spinal cord injury, much work has been done to identify the cellular and molecular factors that control axonal regeneration within the injured central nervous system. This review summarizes the current understanding of a number of the elements within the spinal cord environment that inhibit axonal growth and outlines the factors that influence the neuron’s ability to regenerate its axon after injury. Recent insights in these areas have identified important molecular pathways that are potential targets for therapeutic intervention, raising hope for victims of spinal cord injury., Peer-reviewed article, Published.
Noise in the segmentation gene network of Drosophila, with implications for mechanisms of body axis specification
Specification of the anteroposterior (head-to-tail) axis in the fruit fly Drosophila melanogaster is one of the best understood examples of embryonic pattern formation, at the genetic level. A network of some 14 segmentation genes controls protein expression in narrow domains which are the first manifestation of the segments of the insect body. Work in the New York lab has led to a databank of more than 3300 confocal microscope images, quantifying protein expression for the segmentation genes, over a series of times during which protein pattern is developing (http://flyex.ams.sunysb.edu/FlyEx/). Quantification of the variability in expression evident in this data (both between embryos and within single embryos) allows us to determine error propagation in segmentation signalling. The maternal signal to the egg is highly variable, with noise levels more than several times those seen for expression of downstream genes. This implies that error suppression is active in the embryonic patterning mechanism. Error suppression is not possible with the favoured mechanism of local concentration gradient reading for positional specification. We discuss possible patterning mechanisms which do reliably filter input noise., Peer-reviewed article, Published.
Optimization and single-laboratory validation of a method for the determination of flavonolignans in milk thistle seeds by high-performance liquid chromatography with ultraviolet detection
Seeds of milk thistle, Silybum marianum (L.) Gaertn., are used for treatment and prevention of liver disorders and were identified as a high priority ingredient requiring a validated analytical method. An AOAC International expert panel reviewed existing methods and made recommendations concerning method optimization prior to validation. A series of extraction and separation studies were undertaken on the selected method for determining flavonolignans from milk thistle seeds and finished products to address the review panel recommendations. Once optimized, a single-laboratory validation study was conducted. The method was assessed for repeatability, accuracy, selectivity, LOD, LOQ, analyte stability, and linearity. Flavonolignan content ranged from 1.40 to 52.86 % in raw materials and dry finished products and ranged from 36.16 to 1570.7 μg/mL in liquid tinctures. Repeatability for the individual flavonolignans in raw materials and finished products ranged from 1.03 to 9.88 % RSD, with HorRat values between 0.21 and 1.55. Calibration curves for all flavonolignan concentrations had correlation coefficients of >99.8 %. The LODs for the flavonolignans ranged from 0.20 to 0.48 μg/mL at 288 nm. Based on the results of this single-laboratory validation, this method is suitable for the quantitation of the six major flavonolignans in milk thistle raw materials and finished products, as well as multicomponent products containing dandelion, schizandra berry, and artichoke extracts. It is recommended that this method be adopted as First Action Official Method status by AOAC International., Peer-reviewed article, Published. Received 1 June 2015; Revised 14 July 2015; Accepted 16 July 2015; Published online 31 July 2015.
Pattern selection in plants
Background and Aims A study is made by computation of the interplay between the pattern formation of growth catalysts on a plant surface and the expansion of the surface to generate organismal shape. Consideration is made of the localization of morphogenetically active regions, and the occurrence within them of symmetry-breaking processes such as branching from an initially dome-shaped tip or meristem. Representation of a changing and growing three-dimensional shape is necessary, as two-dimensional work cannot distinguish, for example, formation of an annulus from dichotomous branching. Methods For the formation of patterns of chemical concentrations, the Brusselator reaction-diffusion model is used, applied on a hemispherical shell and generating patterns that initiate as surface spherical harmonics. The initial shape is hemispherical, represented as a mesh of triangles. These are combined into finite elements, each made up of all the triangles surrounding each node. Chemical pattern is converted into shape change by moving nodes outwards according to the concentration of growth catalyst at each, to relieve misfits caused by area increase of the finite element. New triangles are added to restore the refinement of the mesh in rapidly growing regions. Key Results The postulated mechanism successfully generates: tip growth (or stalk extension by an apical meristem) to ten times original hemisphere height; tip flattening and resumption of apical advance; and dichotomous branching and higher-order branching to make whorled structures. Control of the branching plane in successive dichotomous branchings is tackled with partial success and clarification of the issues. Conclusions The representation of a growing plant surface in computations by an expanding mesh that has no artefacts constraining changes of shape and symmetry has been achieved. It is shown that one type of pattern-forming mechanism, Turing-type reaction-diffusion, acting within a surface to pattern a growth catalyst, can generate some of the most important types of morphogenesis in plant development., Peer-reviewed article, Published. Received: 26 July 2007; Returned for revision: 5 October 2007; Accepted: 15 October 2007; Published electronically: 28 November 2007.

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