The University of Alberta is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta, and Henry Marshall Tory, its first president. Its enabling legislation is the Post-secondary Learning Act.The university comprises four campuses in Edmonton, the Augustana Campus in Camrose, and a staff centre in downtown Calgary. The original north campus consists of 150 buildings covering 50 city blocks on the south rim of the North Saskatchewan River valley, directly across from downtown Edmonton. More than 39,000 students from across Canada and 150 other countries participate in nearly 400 programs in 18 faculties.The University of Alberta is a major economic driver in Alberta. The university’s impact on the Alberta economy is an estimated $12.3 billion annually, or five per cent of the province’s gross domestic product. With more than 15,000 employees, the university is Alberta's fourth-largest employer.The university has been recognized by the Academic Ranking of World Universities, the QS World University Rankings and the Times Higher Education World University Rankings as one of the top five universities in Canada and one of the top 100 universities worldwide.According to the 2014 QS World University Rankings the top Faculty Area at the University of Alberta is Arts and Humanities , and the top-ranked Subject is English Language and Literature .The University of Alberta has graduated more than 260,000 alumni, including Governor General Roland Michener, Prime Minister Joe Clark, Chief Justice of Canada Beverley McLachlin, Alberta premiers Peter Lougheed, Dave Hancock and Jim Prentice, Edmonton Mayor Don Iveson and Nobel laureate Richard E. Taylor.The university is a member of the Alberta Rural Development Network, the Association for the Advancement of Sustainability in Higher Education and the Sustainability Tracking, Assessment & Rating System. Wikipedia.
Arefifar S.A.,CANMET Energy |
Mohamed Y.A.-R.I.,University of Alberta |
El-Fouly T.H.M.,CANMET Energy
IEEE Transactions on Smart Grid | Year: 2012
Recently, the concept of microgrids (clusters of distributed generation, energy storage units, and reactive power sources serving a cluster of distributed loads in grid-connected and isolated grid modes) has gained a lot of interest under the smart grid vision. However, there is a strong need to develop systematic procedure for optimal construction of microgrids. This paper presents systematic and optimized approaches for clustering of the distribution system into a set of virtual microgrids with optimized self-adequacy. The probabilistic characteristics of distributed generation (DG) units are also considered by defining two new probabilistic indices representing real and reactive power of the lines. Next, the advantages of installing both distributed energy storage resources (DESRs) and distributed reactive sources (DRSs) are investigated to improve the self-adequacy of the constructed micro-grids. The new strategy facilitates robust infrastructure for smart distribution systems operational control functions, such as self-healing, by using virtual microgrids as building blocks in future distribution systems. The problem formulation and solution algorithms are presented in this paper. The well-known PG&E 69-bus distribution system is selected as a test case and through several sensitivity studies, the effect of the total DESRs or DRSs capacities on the design and the robustness of the algorithm are investigated. © 2010-2012 IEEE.
Wishart D.S.,University of Alberta |
Wishart D.S.,Canadian National Institute For Nanotechnology
TrAC - Trends in Analytical Chemistry | Year: 2013
Recent improvements in nuclear magnetic resonance (NMR) - automation, sensitivity, resolution, pulse-sequence design and spectral processing - are giving novel insights into a wide range of biotech drugs. Real-world applications and emerging trends in biopharmaceutical NMR are being used to help in discovery, design, and characterization of these drugs and to improve assessment of their efficacy, quality and similarity. © 2013 Elsevier Ltd.
Austin W.,University of Alberta
HEC Forum | Year: 2012
Once a term used primarily by moral philosophers, "moral distress" is increasingly used by health professionals to name experiences of frustration and failure in fulfilling moral obligations inherent to their fiduciary relationship with the public. Although such challenges have always been present, as has discord regarding the right thing to do in particular situations, there is a radical change in the degree and intensity of moral distress being expressed. Has the plight of professionals in healthcare practice changed? "Plight" encompasses not only the act of pledging, but that of predicament and peril. The author claims that health professionals are increasingly put in peril by healthcare reform that undermines their efficacy and jeopardizes ethical engagement with those in their care. The re-engineering of healthcare to give precedence to corporate and commercial values and strategies of commodification, service rationing, streamlining, and measuring of "efficiency," is literally demoralizing health professionals. Healthcare practice needs to be grounded in a capacity for compassion and empathy, as is evident in standards of practice and codes of ethics, and in the understanding of what it means to be a professional. Such grounding allows for humane response to the availability of unprecedented advances in biotechnological treatments, for genuine dialogue and the raising of difficult, necessary ethical questions, and for the mutual support of health professionals themselves. If healthcare environments are not understood as moral communities but rather as simulated marketplaces, then health professionals' moral agency is diminished and their vulnerability to moral distress is exacerbated. Research in moral distress and relational ethics is used to support this claim. © 2012 Springer Science+Business Media B.V. All rights reserved.
Johnson M.D.,University of Alberta
Archives of Sexual Behavior | Year: 2013
Utilizing data from all four waves of the National Longitudinal Study of Adolescent Health (Add Health; n = 4,594), the current study explored the direct and indirect effect of parent-child relationship quality during adolescence (Wave 1) on young adult reports of hookup frequency (Wave 4) via alcohol use during adolescence (intercept at Wave 1) and the trajectory of alcohol use across time (slope from Wave 1 through 4). Results from structural equation modeling with a latent growth curve indicated that parent-child relationship quality was related to a lower alcohol use intercept and fewer reported hookups. Both alcohol use slope and intercept were related to more hookups during young adulthood. Bootstrap tests of the indirect paths revealed that, overall, parent-child relationship quality was associated with fewer reported hookups during young adulthood via the mechanism of the alcohol use intercept. © 2013 Springer Science+Business Media New York.
Schneider C.L.,University of Alberta
Proceedings of the Geologists' Association | Year: 2013
Across the Late Devonian biotic crisis, sclerobionts declined in diversity and abundance and the proportions of brachiopod shell textures changed radically. Most of the major sclerobiont clades were common to Givetian through Mississippian ecosystems. Microconchids, most abundant sclerobiont in most Devonian assemblages, were replaced by bryozoans in the Mississippian. Diversity and abundance of Mississippian sclerobionts were lower than Frasnian-Famennian assemblages.Similarities across the Devonian-Mississippian include (a) the encrustation of large brachiopods; (b) gregarious settlement of some sclerobiont taxa; (c) space was not a limiting resource. The similarities and differences in epibiosis across the Devonian-Mississippian suggest potential questions for future study. © 2013 The Geologists' Association.
Fan X.,University of Alberta
Human gene therapy | Year: 2010
The ABO histo-blood group system is the most important antigen system in transplantation medicine, yet no small animal model of the ABO system exists. To determine the feasibility of developing a murine model, we previously subcloned the human alpha-1,2-fucosyltransferase (H-transferase, EC 188.8.131.52) cDNA and the human alpha-1,3-N-acetylgalactosaminyltransferase (A-transferase, EC 184.108.40.206) cDNA into lentiviral vectors to study their ability to induce human histo-blood group A antigen expression on mouse cells. Herein we investigated the optimal conditions for human A and H antigen expression in murine cells. We determined that transduction of a bicistronic lentiviral vector (LvEF1-AH-trs) resulted in the expression of A antigen in a mouse endothelial cell line. We also studied the in vivo utility of this vector to induce human A antigen expression in mouse liver. After intrahepatic injection of LvEF1-AH-trs, A antigen expression was observed on hepatocytes as detected by immunohistochemistry and real-time RT-PCR. In human group A erythrocyte-sensitized mice, A antigen expression in the liver was associated with tissue damage, and deposition of antibody and complement. These results suggest that this gene transfer strategy can be used to simulate the human ABO blood group system in a murine model. This model will facilitate progress in the development of interventions for ABO-incompatible transplantation and transfusion scenarios, which are difficult to develop in clinical or large animal settings.
Goodridge H.S.,Cedars Sinai Medical Center |
Underhill D.M.,Cedars Sinai Medical Center |
Touret N.,University of Alberta
Traffic | Year: 2012
Phagocytosis is a key cellular process, both during homeostasis and upon infection or tissue damage. Receptors on the surface of professional phagocytic cells bind to target particles either directly or through opsonizing ligands, and trigger actin-mediated ingestion of the particles. The process must be carefully controlled to ensure that phagocytosis is triggered efficiently and specifically, and that the antimicrobial cytotoxic responses that often accompany it are initiated only when required. In this review, we will describe and compare the molecular mechanisms that regulate phagocytosis triggered by Fcγ receptors, which mediate the uptake of immunoglobulin G-opsonized targets, and Dectin-1, which is responsible for internalization of fungi with exposed cell wall β-glucan. We will examine how these receptors detect their ligands, how signal transduction is initiated and regulated, and how internalization is instructed to achieve rapid and yet controlled uptake of their targets. © 2012 John Wiley & Sons A/S.
Lamb R.F.,University of Alberta
FEBS Journal | Year: 2012
The act of increasing mass, either in non-dividing cells or in dividing cells seeking to provide new material for daughter cells, depends upon the continued presence of extracellular nutrients in order to conserve mass. For amino acid nutrients, it appears that their insufficiency for new protein synthesis is actively monitored by both prokaryotic and eukaryotic cells, eliciting appropriate cellular responses that may depend not only on bulk nutrient supply, but also on the abundance of specific amino acids. Cell mass increase in both normal and cancer cells requires amino acid nutrients. Insufficiency of amino acid nutrients to promote new protein synthesis is actively monitored by both prokaryotic and eukaryotic cells, eliciting appropriate cellular responses that may depend not only on bulk nutrient supply, but also on the abundance of specific amino acids © 2012 The Author Journal compilation © 2012 FEBS.
Klotz L.-O.,University of Alberta
Archives of Biochemistry and Biophysics | Year: 2012
Posttranscriptional regulation of the biosynthesis of connexins, the building blocks of gap junctional channels, may occur by modulation of connexin mRNA stability and translation. To date, few RNA binding proteins and micro-RNAs (miRNAs) affecting connexin expression are known. Two examples of posttranscriptional regulatory processes resulting in the modulation of gap junctional intercellular communication are the stabilization of connexin-43 mRNA by the RNA binding protein HuR and the blocking effect of miRNAs miR-1 and -206 on connexin-43 mRNA translation. These processes may be affected by stressful stimuli, such as by oxidative stress and environmental factors. Moreover, posttranscriptional regulatory circuits may be involved in the pathogenesis of disease and thus provide suitable targets for therapeutic approaches aiming at altering connexin expression. © 2012 Elsevier Ltd. All rights reserved.
Oba M.,University of Alberta
Canadian Journal of Animal Science | Year: 2011
Sugars are water-soluble carbohydrates that are readily available in the rumen. Although sugars ferment faster than starch or fibre in the rumen, the rates of disaccharide hydrolysis and monosaccharide fermentation vary greatly depending on the type of sugar and rumen environment. Despite rapid fermentation in the rumen and their potentialto provide greater fermentable energy to enhance microbialprotein production, feeding sugars in place of dietary starch sources may not decrease rumen pH or improve N utilization efficiency and milk protein production in dairy cows. However, feeding high-sugar diets often increases dry matter intake, butyrate concentration in the rumen, and milk fat yield. These nutritional characteristics of sugars may allow us to use high-sugar feedstuffs as an alternative energy source for lactating dairy cows to increase dietary energy density with reduced risk of rumen acidosis, but there is little evidence in the literature to indicate that the synchrony of rumen fermentation would be enhanced by feeding high-sugar diets with high soluble protein. Greater butyrate production from feeding high-sugar diets is expected to enhance proliferation of gut tissues, but its physiological mechanisms and effects of butyrate metabolism on overall productivity of dairy cows warrant further investigations.
Chung J.H.,U.S. National Institutes of Health |
Manganiello V.,U.S. National Institutes of Health |
Dyck J.R.B.,University of Alberta
Trends in Cell Biology | Year: 2012
It is widely believed that calorie restriction (CR) can extend the lifespan of model organisms and protect against aging-related diseases. A potential CR mimetic is resveratrol, which may have beneficial effects against numerous diseases such as type 2 diabetes, cardiovascular diseases, and cancer in tissue culture and animal models. However, resveratrol in its current form is not ideal as therapy, because even at very high doses it has modest efficacy and many downstream effects. Identifying the cellular targets responsible for the effects of resveratrol and developing target-specific therapies will be helpful in increasing the efficacy of this drug without increasing its potential adverse effects. A recent discovery suggests that the metabolic effects of resveratrol may be mediated by inhibiting cAMP phosphodiesterases (PDEs), particularly PDE4. Here, we review the current literature on the metabolic and cardiovascular effects of resveratrol and attempt to shed light on the controversies surrounding its action. © 2012.
James Shapiro A.M.,University of Alberta
Review of Diabetic Studies | Year: 2012
Remarkable progress has been made in islet transplantation over a span of 40 years. Once just an experimental curiosity in mice, this therapy has moved forward, and can now provide robust therapy for highly selected patients with type 1 diabetes (T1D), refractory to stabilization by other means. This progress could not have occurred without extensive dynamic international collaboration. Currently, 1,085 patients have undergone islet transplantation at 40 international sites since the Edmonton Protocol was reported in 2000 (752 allografts, 333 autografts), according to the Collaborative Islet Transplant Registry. The long-term results of islet transplantation in selected centers now match registry data of pancreas-alone transplantation, with 6 sites reporting five-year insulin independence rates ≥50%. Islet transplantation has been criticized for the use of multiple donor pancreas organs, but progress has also occurred in single-donor success, with 10 sites reporting increased single-donor engraftment. The next wave of innovative clinical trial interventions will address instant blood-mediated inflammatory reaction (IBMIR), apoptosis, and inflammation, and will translate into further marked improvements in single-donor success. Effective control of auto- and alloimmunity is the key to longterm islet function, and high-resolution cellular and antibody- based assays will add considerable precision to this process. Advances in immunosuppression, with new antibody- based targeting of costimulatory blockade and other TB cellular signaling, will have further profound impact on the safety record of immunotherapy. Clinical trials will move forward shortly to test out new human stem cell derived islets, and in parallel trials will move forward, testing pig islets for compatibility in patients. Induction of immunological tolerance to self-islet antigens and to allografts is a difficult challenge, but potentially within our grasp. © by Lab & Life Press/SBDR.
Ballard-Barbash R.,U.S. National Institutes of Health |
Friedenreich C.M.,Alberta Health Services Cancer Care |
Courneya K.S.,University of Alberta |
Siddiqi S.M.,U.S. National Institutes of Health |
And 2 more authors.
Journal of the National Cancer Institute | Year: 2012
Background Cancer survivors often seek information about how lifestyle factors, such as physical activity, may influence their prognosis. We systematically reviewed studies that examined relationships between physical activity and mortality (cancer-specific and all-cause) and/or cancer biomarkers.MethodsWe identified 45 articles published from January 1950 to August 2011 through MEDLINE database searches that were related to physical activity, cancer survival, and biomarkers potentially relevant to cancer survival. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement to guide this review. Study characteristics, mortality outcomes, and biomarker-relevant and subgroup results were abstracted for each article that met the inclusion criteria (ie, research articles that included participants with a cancer diagnosis, mortality outcomes, and an assessment of physical activity).ResultsThere was consistent evidence from 27 observational studies that physical activity is associated with reduced all-cause, breast cancer-specific, and colon cancer-specific mortality. There is currently insufficient evidence regarding the association between physical activity and mortality for survivors of other cancers. Randomized controlled trials of exercise that included biomarker endpoints suggest that exercise may result in beneficial changes in the circulating level of insulin, insulin-related pathways, inflammation, and, possibly, immunity; however, the evidence is still preliminary.ConclusionsFuture research directions identified include the need for more observational studies on additional types of cancer with larger sample sizes; the need to examine whether the association between physical activity and mortality varies by tumor, clinical, or risk factor characteristics; and the need for research on the biological mechanisms involved in the association between physical activity and survival after a cancer diagnosis. Future randomized controlled trials of exercise with biomarker and cancer-specific disease endpoints, such as recurrence, new primary cancers, and cancer-specific mortality in cancer survivors, are warranted. © 2012 The Author.
Harvey S.,University of Alberta
General and Comparative Endocrinology | Year: 2013
Pituitary GH is obligatory for normal growth in mammals, but the importance of pituitary GH in avian growth is less certain. In birds, pituitary GH is biologically active and has growth promoting actions in the tibia-test bioassay. Its importance in normal growth is indicated by the growth suppression following the surgical removal of the pituitary gland or after the immunoneutralization of endogenous pituitary GH. The partial restoration of growth in some studies with GH-treated hypophysectomized birds also suggests GH dependency in avian growth, as does the dwarfism that occurs in some strains with GHR dysfunctions. Circulating GH concentrations are also correlated with body weight gain, being high in young, rapidly growing birds and low in slower growing older birds. Nevertheless, despite these observations, there is an extensive literature that concludes pituitary GH is not important in avian growth. This is based on numerous studies with hypophysectomized and intact birds that show only slight, transitory or absent growth responses to exogenous GH-treatment. Moreover, while circulating GH levels correlate with weight gain in young birds, this may merely reflect changes in the control of pituitary GH secretion during aging, as numerous studies involving experimental alterations in growth rate fail to show positive correlations between plasma GH concentrations and the alterations in growth rate. Furthermore, growth is known to occur in the absence of pituitary GH, as most embryonic development occurs prior to the ontogenetic appearance of pituitary somatotrophs and the appearance of GH in embryonic circulation. Early embryonic growth is also independent of the endocrine actions of pituitary GH, since removal of the presumptive pituitary gland does not impair early growth. Embryonic growth does, however, occur in the presence of extrapituitary GH, which is produced by most tissues and has autocrine or paracrine roles that locally promote growth and development. The role of GH in avian growth is therefore still unclear. © 2013 Elsevier Inc.
Van Der Heijde D.,Leiden University |
Maksymowych W.P.,University of Alberta
Annals of the Rheumatic Diseases | Year: 2010
Advances in the understanding of this group of arthritides over the past decade can be considered transformational from the perspective of basic mechanisms as well as clinical research focusing on the development of imaging technologies and a spectrum of standardised clinical outcomes that aim at a more comprehensive understanding of disease activity, functioning and disability, and prognosis. Prior to this decade, treatment was unsatisfactory and limited to physical modalities and non-steroidal anti-inflammatory agents, while diagnostic ascertainment primarily focused on clinical evaluation and plain radiography. Today, patients with spondyloarthritis (SpA) can look forward to earlier diagnosis and more effective treatment but significant challenges remain. This review will summarise the past decade's major accomplishments in the understanding of the basic mechanisms contributing to the development of SpA, outline those advances in clinical and imaging outcomes that have enabled major therapeutic advances and now permit a broader understanding of the early development of disease and its impact on patient well-being, and will describe new approaches to the development of diagnostic criteria that incorporate advances in imaging.
Spratlin J.,University of Alberta
Current Oncology Reports | Year: 2011
Angiogenesis, a well-recognized characteristic of malignancy, has been exploited more than any other pathway targeted by biologic anti-neoplastic therapies. Vascular endothelial growth factor receptor-2 (VEGFR-2) is the critical receptor involved in malignant angiogenesis with its activation inducing a number of other cellular modifications resulting in tumor growth and metastases. Ramucirumab (IMC-1121B; ImClone Systems Corporation, Branchburg, NJ) is a fully human monoclonal antibody developed to specifically inhibit VEGFR-2. Ramucirumab is currently being investigated in multiple clinical trials across a variety of tumor types. Herein, angiogenesis inhibition in cancer is reviewed and up-to-date information on the clinical development of ramucirumab is presented. © Springer Science+Business Media, LLC 2011.
Hazes B.,University of Alberta
BMC Bioinformatics | Year: 2014
Background: Protein-coding DNA sequences and their corresponding amino acid sequences are routinely used to study relationships between sequence, structure, function, and evolution. The rapidly growing size of sequence databases increases the power of such comparative analyses but it makes it more challenging to prepare high quality sequence data sets with control over redundancy, quality, completeness, formatting, and labeling. Software tools for some individual steps in this process exist but manual intervention remains a common and time consuming necessity.Description: CDSbank is a database that stores both the protein-coding DNA sequence (CDS) and amino acid sequence for each protein annotated in Genbank. CDSbank also stores Genbank feature annotation, a flag to indicate incomplete 5′ and 3′ ends, full taxonomic data, and a heuristic to rank the scientific interest of each species. This rich information allows fully automated data set preparation with a level of sophistication that aims to meet or exceed manual processing. Defaults ensure ease of use for typical scenarios while allowing great flexibility when needed. Access is via a free web server at http://hazeslab.med.ualberta.ca/CDSbank/.Conclusions: CDSbank presents a user-friendly web server to download, filter, format, and name large sequence data sets. Common usage scenarios can be accessed via pre-programmed default choices, while optional sections give full control over the processing pipeline. Particular strengths are: extract protein-coding DNA sequences just as easily as amino acid sequences, full access to taxonomy for labeling and filtering, awareness of incomplete sequences, and the ability to take one protein sequence and extract all synonymous CDS or identical protein sequences in other species. Finally, CDSbank can also create labeled property files to, for instance, annotate or re-label phylogenetic trees. © 2014 Hazes; licensee BioMed Central Ltd.
Greer J.J.,University of Alberta
Respiratory Physiology and Neurobiology | Year: 2013
This review outlines research that has advanced our understanding of the pathogenesis and etiology of congenital diaphragmatic hernia (CDH). The majority of CDH cases involve incomplete formation of the posterolateral portion of the diaphragm, clinically referred to as a Bochdalek hernia. The hole in the diaphragm allows the abdominal viscera to invade the thoracic cavity, thereby impeding normal lung development. As a result, newborns with CDH suffer from a combination of severe pulmonary hypoplasia and pulmonary hypertension. Despite advances in neonatal intensive care, mortality and serious morbidity remain high. Systematic studies using rat and transgenic mouse models in conjunction with analyses of human tissue are providing insights into the embryological origins of the diaphragmatic defect associated with CDH and abnormalities of developmentally regulated signaling cascades. © 2013 Elsevier B.V.
Van Manen M.A.,University of Alberta
Qualitative Health Research | Year: 2014
This study was a phenomenological investigation of ethical decisions experienced by parents of newborns in neonatal intensive care. I explore the lived meanings of thematic events that speak to the variable ways that ethical situations may be experienced: a decision that was never a choice; a decision as looking for a way out; a decision as thinking and feeling oneself through the consequences; a decision as indecision; and a decision as something that one falls into. The concluding recommendations spell out the need for understanding the experiences of parents whose children require medical care and underscore the tactful sensitivities required of the health care team during moral-ethical decision making. © The Author(s) 2014.
Tsui B.C.,University of Alberta
Anaesthesia | Year: 2014
Using a simple surface nerve stimulation system, I examined the effects of general anaesthesia on rheobase (the minimum current required to stimulate nerve activity) and chronaxie (the minimum time for a stimulus twice the rheobase to elicit nerve activity). Nerve stimulation was used to elicit a motor response from the ulnar nerve at varying pulse widths before and after induction of general anaesthesia. Mean (SD) rheobase before and after general anaesthesia was 0.91 (0.37) mA (95% CI 0.77-1.04 mA) and 1.11 (0.53) mA (95% CI 0.92-1.30 mA), respectively. Mean (SD) chronaxie measured before and after general anaesthesia was 0.32 (0.17) ms (95% CI 0.26-0.38 ms) and 0.29 (0.13) ms (95% CI 0.24-0.33 ms), respectively. Under anaesthesia, rheobase values increased by an average of 20% (p = 0.05), but chronaxie values did not change significantly (p = 0.39). These results suggest that threshold currents used for motor response from nerve stimulation under general anaesthesia might be higher than those used in awake patients. © 2014 The Association of Anaesthetists of Great Britain and Ireland.
Vance J.E.,University of Alberta |
Karten B.,Dalhousie University
Journal of Lipid Research | Year: 2014
Niemann-Pick type C (NPC) disease is a lysosomal storage disease in which endocytosed cholesterol becomes sequestered in late endosomes/lysosomes (LEs/Ls) because of mutations in either the NPC1 or NPC2 gene. Mutations in either of these genes can lead to impaired functions of the NPC1 or NPC2 proteins and progressive neurodegeneration as well as liver and lung disease. NPC1 is a polytopic protein of the LE/L limiting membrane, whereas NPC2 is a soluble protein in the LE/L lumen. These two proteins act in tandem and promote the export of cholesterol from LEs/Ls. Consequently, a defect in either NPC1 or NPC2 causes cholesterol accumulation in LEs/Ls. In this review, we summarize the molecular mechanisms leading to NPC disease, particularly in the CNS. Recent exciting data on the mechanism by which the cholesterol-sequestering agent cyclodextrin can bypass the functions of NPC1 and NPC2 in the LEs/Ls, and mobilize cholesterol from LEs/Ls, will be highlighted. Moreover, the possible use of cyclodextrin as a valuable therapeutic agent for treatment of NPC patients will be considered. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.
Requena J.R.,University of Santiago de Compostela |
Wille H.,University of Alberta
Prion | Year: 2014
The structures of the infectious prion protein, PrPSc, and that of its proteolytically truncated variant, PrP 27-30, have evaded experimental determination due to their insolubility and propensity to aggregate. Molecular modeling has been used to fill this void and to predict their structures, but various modeling approaches have produced significantly different models. The disagreement between the different odelingsolutions indicates the limitations of this method. Over the years, in absence of a three-dimensional (3D) structure, a variety of experimental techniques have been used to gain insights into the structure of this biologically, medically, and agriculturally important isoform. Here, we present an overview of experimental results that were published in recent years, and which provided new insights into the molecular architecture of PrPSc and PrP 27-30. Furthermore, we evaluate all published models in light of these recent, experimental data, and come to the conclusion that none of the models can accommodate all of the experimental constraints. Moreover, this conclusion constitutes an open invitation for renewed efforts to model the structure of PrPSc.©2014 Landes Bioscience.
Fuster D.G.,University of Bern |
Alexander R.T.,University of Alberta
Pflugers Archiv European Journal of Physiology | Year: 2014
The SLC9 gene family encodes Na+/H+ exchangers (NHEs). These transmembrane proteins transport ions across lipid bilayers in a diverse array of species from prokaryotes to eukaryotes, including plants, fungi, and animals. They utilize the electrochemical gradient of one ion to transport another ion against its electrochemical gradient. Currently, 13 evolutionarily conserved NHE isoforms are known in mammals [22, 46, 128]. The SLC9 gene family (solute carrier classification of transporters: www.bioparadigms.org) is divided into three subgroups . The SLC9A subgroup encompasses plasmalemmal isoforms NHE1-5 (SLC9A1-5) and the predominantly intracellular isoforms NHE6-9 (SLC9A6-9). The SLC9B subgroup consists of two recently cloned isoforms, NHA1 and NHA2 (SLC9B1 and SLC9B2, respectively). The SLC9C subgroup consist of a sperm specific plasmalemmal NHE (SLC9C1) and a putative NHE, SLC9C2, for which there is currently no functional data . NHEs participate in the regulation of cytosolic and organellar pH as well as cell volume. In the intestine and kidney, NHEs are critical for transepithelial movement of Na+ and HCO3 - and thus for whole body volume and acid-base homeostasis . Mutations in the NHE6 or NHE9 genes cause neurological disease in humans and are currently the only NHEs directly linked to human disease. However, it is becoming increasingly apparent that members of this gene family contribute to the pathophysiology of multiple human diseases. © 2013 Springer-Verlag Berlin Heidelberg.
Zhao H.,University of Alberta |
Su W.,State University of New York at Buffalo
IEEE Transactions on Wireless Communications | Year: 2010
The popularity of multimedia multicast/broadcast applications over wireless networks makes it critical to address the error-prone, heterogeneous and dynamically changing nature of wireless channels. A promising solution to combat channel fading is to explore the cooperative diversity in which users may help each other forward packets. This paper investigates cooperative multicast schemes that use a maximal ratio combiner to enhance the received signal-to-noise ratio (SNR), and provides a thorough performance analysis. Two relay selection schemes are considered: the distributed and the genie-aided cooperation schemes. We derive the closed-form formulation and the approximations of their average outage probabilities.We also analyze the optimal power allocation and relay location strategies, and show that allocating half of the total transmission power to the source minimizes the average outage probability. Our analysis and simulation results show that cooperative multicast gives better performance when more relays help forward signals. Cooperative multicast helps achieve diversity order 2, and user cooperation can significantly reduce the outage probability, especially in the high SNR region. Finally, we compare the two cooperation strategies, and show that distributed cooperative multicast is preferred since it achieves a lower outage probability without introducing extra overhead for control messages. © 2010 IEEE.
Abourizk S.,University of Alberta
Journal of Construction Engineering and Management | Year: 2010
Construction simulation is the science of developing and experimenting with computer-based representations of construction systems to understand their underlying behavior. This branch of operations research applications in construction management has experienced significant academic growth over the past two decades. In this paper, the author summarizes his views on this topic as per his Peurifoy address, given in October 2008. The paper provides an overview of advancements in construction simulation theory as reported in literature. It then summarizes the key factors that contribute to successful deployment of simulation in the construction industry, and the key attributes of problems that make them more amenable for simulation modeling as opposed to other tools. The paper then provides an overview of long-term simulation initiatives leading to the next generation of computer modeling systems for construction, where simulation plays an integral role in a futuristic vision of automated project planning and control. © 2010 ASCE.
Tan A.,University of Alberta
Medical education online | Year: 2013
The dying patient is a reality of medicine. Medical students, however, feel unprepared to effectively manage the complex end-of-life (EOL) management issues of the dying patient and want increased experiential learning in Palliative Care. To address the need for more formal curriculum in EOL care, we developed and implemented an online virtual patient (VP) clinical case in Palliative Care into the 2010-2011 Year Three Family Medicine Clerkship rotation curriculum. A mixed-method design was used to measure the change in knowledge and perceived preparedness level in EOL care before and after completing the online VP case. A survey collected qualitative descriptions of the students' educational experience of using this case. Ninety five percent (130/137) of the students voluntarily consented to have their results analyzed. The group knowledge score (n=127) increased significantly from a pre-course average of 7.69/16±2.27, to a post-course average of 10.02/16±2.39 (p<0.001). The students' self-assessed comfort level increased significantly with all aspects of EOL management from pre-course to post-course (p<0.001). Nearly, 91.1% of the students rated the VP realism as 'Good to Excellent', 86% rated the case as educationally beneficial. Nearly 59.3% of students felt emotionally engaged with the VP. Qualitative feedback found that the case content was very useful and realistic, but that the interface was sometimes awkward to navigate. The online VP case in Palliative Care is a useful teaching tool that may help to address the need for increased formal Palliative Care experience in medical school training programs.
Maksymowych W.P.,University of Alberta
Nature Reviews Rheumatology | Year: 2010
The concept of disease modification in ankylosing spondylitis (AS) incorporates aspects of inflammation, bone destruction and new bone formation. The degree to which inflammation and new bone formation are linked remains conjectural, but data from MRI studies of spinal inflammation support the concept of such coupling; however, these studies also suggest a role for the involvement of noninflammatory pathways, such as those involving bone morphogenetic proteins, wingless proteins and Dickkopf-1, in the formation of new bone. The main clinical outcome that reflects disease modification is the modified Stoke Ankylosing Spondylitis Spine Score, which assesses abnormalities in the anterior vertebral corners of the cervical and lumbar spine. However, radiographic progression can only be reliably detected using this method after at least 2 years, and this delay precludes the conduct of placebo-controlled trials on ethical grounds. Preliminary data using this scoring tool suggest that cyclooxygenase-2-selective NSAIDs might reduce disease progression if used continuously over 2 years. By contrast, three different anti-tumor necrosis factor therapies have shown no impact on radiographic progression. Therapeutic trials recruiting patients early in their disease course and at high risk of radiographic progression constitute a high priority for clinical research in AS. © 2010 Macmillan Publishers Limited. All rights reserved.
Jugdutt B.I.,University of Alberta
Expert Review of Cardiovascular Therapy | Year: 2010
The elderly population (age ≥65 years) is increasing, and with it the prevalence of heart failure and associated morbidity, hospitalizations and costs. Despite advances, clinical trial data on heart failure therapy exclusively for elderly patients are lacking. However, trials of therapy for heart failure with left ventricular systolic dysfunction or low ejection fraction in primarily non-elderly patients showed mortality benefit in elderly patients. By contrast, trials for heart failure with normal left ventricular systolic function or preserved ejection fraction have not shown mortality benefit in elderly or non-elderly patients. Heart failure pharmacotherapy in the elderly is challenging; it needs to be individualized and consider aging-specific changes in physiology, drug metabolism, drug pharmacokinetics and tolerance, comorbidities, polypharmacy and drug-drug interactions that can contribute to adverse effects. More research into the biology of aging and clinical trials in elderly patients may lead to the discovery of new therapies for heart failure in the elderly. © 2010 Expert Reviews Ltd.
Shafran S.D.,University of Alberta
Clinical Infectious Diseases | Year: 2015
Phase 3 trials of direct acting antiviral drugs (DAAs) for hepatitis C virus (HCV) excluded patients coinfected with human immunodeficiency virus (HIV). After approval, small trials were done in HIV-HCV coinfected patients. The status quo results in delayed access to DAAs for HIV coinfected patients, a group with more rapid progression of liver disease. This article reviews all approved DAAs and compares sustained virological response (SVR) rates in the HIV coinfected with those in the HCV monoinfected treated with the same regimen for the same HCV genotype. SVR rates in HCV genotype 1 to 4 are virtually identical in the HIV co-infected as in the HCV monoinfected, regardless of whether the regimens contain interferon. Because HIV coinfection does not affect SVR rates or toxicity with DAA-containing therapy, excluding HIV coinfected patients from clinical trials of DAA-containing anti-HCV therapy is discriminatory and unnecessary. Rather, HIV coinfection is one of many comorbidities that occur in some patients with HCV infection. © 2015 The Author.
Lacy P.,University of Alberta
Blood | Year: 2014
In this issue of Blood, Percopo et al provide intriguing new evidence supporting a role for eosinophils in protecting mice against the lethal effects of respiratory virus infection. © 2014 by The American Society of Hematology.
Hendzel M.J.,University of Alberta
Current Opinion in Cell Biology | Year: 2014
The presence and state of actin in the nucleus has long been controversial. This is poised to change. Over the past two years, the regulation of nuclear actin and its polymerization have begun to be characterized. The transport of actin into and out of the nucleus has been defined and the importance of nuclear actin polymerization in the retention of the serum response factor coactivator MRTF-A is now quite clear. Moreover, serum-starved fibroblasts that are stimulated with serum rapidly form long actin bundles that can be visualized using the F-actin binding drug phalloidin. This provides the first compelling direct evidence that actin polymerizes in the nucleus and provides the foundation for a serious investigation of the function(s) of nuclear polymeric actin. © 2014 Elsevier Ltd.
Fallone B.G.,University of Alberta
Seminars in Radiation Oncology | Year: 2014
We have successfully built linac-magnetic resonance imaging (MR) systems based on a linac waveguide placed between open MR planes (perpendicular) or through the central opening of one of the planes (parallel) to improve dosimetric properties. It rotates on a gantry to irradiate at any angle. Irradiation during MR imaging and automatic 2-dimensional MR image-based target tracking and automatic beam steering to the moving target have been demonstrated with our systems. The functioning whole-body system (0.6-T MR and 6-MV linac) has been installed in an existing clinical vault without removing the walls or the ceiling and without the need of a helium exhaust vent. © 2014 Elsevier Inc.
Joffe A.R.,University of Alberta
Critical Care Medicine | Year: 2012
Hart et al (7) should be commended for performing this survey of clinicians' perceptions of DCDD. For this intensiv-ist, the survey raises concerns about the process of DCDD, informed consent, and the COI involved. The next questions to ask should aim to determine clinicians' knowledge of the controversies involved, and their informed opinions regarding these controversies.
Dornstauder B.,University of Alberta
Investigative ophthalmology & visual science | Year: 2012
With age, retina function progressively declines and A2E, a constituent of the toxin lipofuscin, accumulates in retinal pigment epithelial (RPE) cells. Both events are typically exacerbated in age-related retina diseases. We studied the effect of dietary docosahexaenoic acid (DHA, C22:6n-3) supplementation on these events, using a transgenic mouse model (mutant human ELOVL4; E4) displaying extensive age-related retina dysfunction and massive A2E accumulation. Retina function was assessed with the electroretinogram (ERG) and A2E levels were measured in E4 and wildtype (WT) mice. Dietary DHA was manipulated from 1 to 3, 1 to 6, 6 to 12, and 12 to 18 months: 1% DHA over total fatty acids (E4+, WT+) or similar diet without DHA (E4-, WT-). Increased omega-3/6 ratios (DHA/arachidonic acid) in E4+ and WT+ retinas were confirmed for the 1- to 3-month and 1- to 6-month trials. Although 1- to 3-month intervention had no effects, when prolonged to 1 to 6 months, RPE function (ERG c-wave) was preserved in E4+ and WT+. Intervention from 6 to 12 months led to maintained outer and inner retina function (ERG a- and b-wave, respectively) in E4+. At 12 to 18 months, a similar beneficial effect on retina function occurred in WT+; A2E levels were reduced in E4+ and WT+. DHA supplementation was associated with: preserved retina function at mid-degenerative stages in E4 mice; prevention of age-related functional losses in WT mice; and reduced A2E levels in E4 and WT mice at the oldest age examined. These findings imply that dietary DHA could have broad preventative therapeutic applications (acting on pathologic and normal age-related ocular processes).
O'Reilly M.,University of Alberta |
Thebaud B.,Ottawa Hospital Research Institute
American Journal of Physiology - Lung Cellular and Molecular Physiology | Year: 2014
Bronchopulmonary dysplasia (BPD) is the chronic lung disease of prematurity that affects very preterm infants. Although advances in perinatal care have enabled the survival of infants born as early as 23–24 wk of gestation, the challenge of promoting lung growth while protecting the ever more immature lung from injury is now bigger. Consequently, BPD remains one of the most common complications of extreme prematurity and still lacks specific treatments. Progress in our understanding of BPD and the potential of developing therapeutic strategies have arisen from large (baboons, sheep, and pigs) and small (rabbits, rats, and mice) animal models. This review focuses specifically on the use of the rat to model BPD and summarizes how the model is used in various research studies and the advantages and limitations of this particular model, and it highlights recent therapeutic advances in BPD by using this rat model. © 2014 the American Physiological Society.
Painter K.J.,Heriot - Watt University |
Hillen T.,University of Alberta
Physica D: Nonlinear Phenomena | Year: 2011
In this paper we explore the dynamics of a one-dimensional KellerSegel type model for chemotaxis incorporating a logistic cell growth term. We demonstrate the capacity of the model to self-organise into multiple cellular aggregations which, according to position in parameter space, either form a stationary pattern or undergo a sustained spatio-temporal sequence of merging (two aggregations coalesce) and emerging (a new aggregation appears). This spatio-temporal patterning can be further subdivided into either a time-periodic or time-irregular fashion. Numerical explorations into the latter indicate a positive Lyapunov exponent (sensitive dependence to initial conditions) together with a rich bifurcation structure. In particular, we find stationary patterns that bifurcate onto a path of periodic patterns which, prior to the onset of spatio-temporal irregularity, undergo a "periodic-doubling" sequence. Based on these results and comparisons with other systems, we argue that the spatio-temporal irregularity observed here describes a form of spatio-temporal chaos. We discuss briefly our results in the context of previous applications of chemotaxis models, including tumour invasion, embryonic development and ecology. © 2010 Elsevier B.V. All rights reserved.
West L.J.,University of Alberta
Current Opinion in Organ Transplantation | Year: 2011
Purpose of Review: The practice of offering ABO-incompatible (ABOi) heart transplantation during infancy was initiated based on the rationale that infants are at the highest risk of dying while waiting for a transplant, yet are at low risk of hyperacute antibody-mediated rejection due to immunologic immaturity. Since the first report of intentional ABOi heart transplantation a decade ago, its success has been corroborated in numerous reports and the practice has been widely adopted. This review summarizes clinical results in reports of ABOi transplantation and the evolution of ABOi listing strategies, as well as evidence of immune tolerance after ABOi transplantation. Recent Findings: Recent reports have documented comparable midterm and long-term clinical outcomes in ABOi and ABO-compatible (ABOc) heart transplant recipients in terms of survival and posttransplant complications. Despite successful outcomes, however, there are obstacles to widespread implementation of ABOi transplantation in the USA and in some European centers. The notable deficiency in development of antibody production to donor A/B antigens following ABOi transplantation described in early reports has been corroborated, with some exceptions. Potential advantages of ABOi transplantation are emerging as well as innovative strategies that may allow ABOi heart transplantation beyond the age of infancy. Summary: ABOi heart transplantation is one example in which immunologic immaturity has been exploited to the advantage of pediatric transplant recipients. In-depth exploration of transplant-related immunobiology in the young may reveal further opportunities. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Agborsangaya C.B.,University of Alberta
BMC public health | Year: 2012
Studies on the prevalence of multimorbidity, defined as having two or more chronic conditions, have predominantly focused on the elderly. We estimated the prevalence and specific patterns of multimorbidity across different adult age groups. Furthermore, we examined the associations of multimorbidity with socio-demographic factors. Using data from the Health Quality Council of Alberta (HQCA) 2010 Patient Experience Survey, the prevalence of self reported multimorbidity was assessed by telephone interview among a sample of 5010 adults (18 years and over) from the general population. Logistic regression analyses were performed to determine the association between a range of socio-demographic factors and multimorbidity. The overall age- and sex-standardized prevalence of multimorbidity was 19.0% in the surveyed general population. Of those with multimorbidity, 70.2% were aged less than 65 years. The most common pairing of chronic conditions was chronic pain and arthritis. Age, sex, income and family structure were independently associated with multimorbidity. Multimorbidity is a common occurrence in the general adult population, and is not limited to the elderly. Future prevention programs and practice guidelines should take into account the common patterns of multimorbidity.
Montano-Loza A.J.,University of Alberta
World Journal of Gastroenterology | Year: 2014
The most commonly recognized complications in cirrhotic patients include ascites, hepatic encephalopathy, variceal bleeding, susceptibility for infections, kidney dysfunction, and hepatocellular carcinoma; however, severe muscle wasting or sarcopenia are the most common and frequently unseen complications which negatively impact survival, quality of life, and response to stressor, such as infections and surgeries. At present, D'Amico stage classification, Child-Pugh, and MELD scores constitute the best tools to predict mortality in patients with cirrhosis; however, one of their main limitations is the lack of assessing the nutritional and functional status. Currently, numerous methods are available to evaluate the nutrition status of the cirrhotic patient; nevertheless, most of these techniques have limitations primarily because lack of objectivity, reproducibility, and prognosis discrimination. In this regard, an objective and reproducible technique, such as muscle mass quantification with cross-sectional imaging studies (computed tomography scan or magnetic resonance imaging) constitute an attractive index of nutritional status in cirrhosis. Sarcopenia is part of the frailty complex present in cirrhotic patients, resulting from cumulative declines across multiple physiologic systems and characterized by impaired functional capacity, decreased reserve, resistance to stressors, and predisposition to poor outcomes. In this review, we discuss the current accepted and new methods to evaluate prognosis in cirrhosis. Also, we analyze the current knowledge regarding incidence and clinical impact of malnutrition and sarcopenia in patients with cirrhosis and their impact after liver transplantation. Finally, we discuss existing and potential novel therapeutic approaches for malnutrition in cirrhosis, emphasizing the recognition of sarcopenia in an effort to reduced morbidity related and improved survival in cirrhosis. © 2014 Baishideng Publishing Group Inc. All rights reserved.
McCreery R.L.,University of Alberta
Chemical Record | Year: 2012
Molecular Electronics has the potential to greatly enhance existing silicon-based microelectronics to realize new functions, higher device density, lower power consumption, and lower cost. Although the investigation of electron transport through single molecules and molecular monolayers in "molecular junctions" is a recent development, many of the relevant concepts and phenomena are derived from electrochemistry, as practiced for the past several decades. The past 10+ years have seen an explosion of research activity directed toward how the structure of molecules affects electron transport in molecular junctions, with the ultimate objective of "rational design" of molecular components with new electronic functions, such as chemical sensing, interactions with light, and low-cost, low-power consumer electronics. In order to achieve these scientifically and commercially important objectives, the factors controlling charge transport in molecules "connected" to conducting contacts must be understood, and methods for massively parallel manufacturing of molecular circuits must be developed. This Personal Account describes the development of reproducible and robust molecular electronic devices, starting with modified electrodes used in electrochemistry and progressing to manufacturable molecular junctions. Although the field faced some early difficulties in reliability and characterization, the pieces are now in place for rapid advances in understanding charge transport at the molecular level. Inherent in the field of Molecular Electronics are many electrochemical concepts, including tunneling, redox exchange, activated electron transfer, and electron coupling between molecules and conducting contacts. Copyright © 2012 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.
Armijo-Olivo S.,University of Alberta
Journal of orofacial pain | Year: 2011
To determine whether patients with myogenous or mixed (ie, myogeneous plus arthrogeneous) temporomandibular disorders (TMD) had different head and cervical posture measured through angles commonly used in clinical research settings when compared to healthy individuals. One hundred fifty-four persons participated in this study. Of these, 50 subjects were healthy, 55 subjects had myogenous TMD, and 49 subjects had mixed TMD (ie, arthrogenous plus myogenous TMD). A lateral photograph was taken with the head in the self-balanced position. Four angles were measured in the photographs: (1) Eye-Tragus-Horizontal, (2) Tragus-C7-Horizontal, (3) Pogonion-Tragus-C7, and (4) Tragus-C7-Shoulder. Alcimagen software specially designed to measure angles was used in this study. All of the measurements were performed by a single trained rater, a dental specialist in orthodontics, blinded to each subject's group status. The only angle that reached statistical significance among groups was the Eye-Tragus-Horizontal (F = 3.03, P = .040). Pairwise comparisons determined that a mean difference of 3.3 degrees (95% confidence intervals [CI]: 0.15, 6.41) existed when comparing subjects with myogenous TMD and healthy subjects (P = .036). Postural angles were not significantly related to neck disability, jaw disability, or pain intensity. Intrarater and interrater reliability of the measurements were excellent, with intraclass correlation coefficient (ICC) values ranging between 0.996-0.998. The only statistically significant difference in craniocervical posture between patients with myogenous TMD and healthy subjects was for the Eye-Tragus-Horizontal angle, indicating a more extended position of the head. However, the difference was very small (3.3 degrees) and was judged not to be clinically significant.
Zemp R.J.,University of Alberta
Applied Optics | Year: 2010
Quantitative imaging of optical properties of biological tissues with high resolution has beena long-sought-after goal of many research groups. Photoacoustic imaging is a hybrid bio-optical imaging technique offering optical absorption contrast with ultrasonic spatial resolution. While photoacoustic methods offer significant promise for high-resolution optical imaging, quantification has thus far proved challenging. In this paper, a noniterative reconstruction technique for producing quantitative photoacoustic images of absorption perturbations is introduced for the case when the optical propertiesof the turbid background are known and when multiple optical illumination locations are used. Through theoretical developments and computational examples it is demonstrated that multiple-optical-source photoacoustic imaging can produce quantitative optical absorption reconstructions. The combination of optical and photoacoustic measurements is shown to yield improved reconstruction stability. © 2010 Optical Society of America.
Houghton M.,University of Alberta
Science Translational Medicine | Year: 2012
A hepatitis C virus vaccine delivered by a chimpanzee-derived adenovirus vector produces strong T cell immune responses in healthy human volunteers.
Scott C.T.,Center for Biomedical Ethics |
Scott C.T.,University of British Columbia |
Caulfield T.,University of Alberta |
Borgelt E.,University of British Columbia |
Illes J.,University of British Columbia
Nature Biotechnology | Year: 2012
As the healthcare industry moves from a twentieth century approach of providing treatments of last resort to a future of individualized medicine, biobanks will play a pivotal role in this transition. Yet at the cutting edge of biobanking research are new ethical, social and policy challenges beyond those familiar to basic biomedical research. © 2012 Nature America, Inc. All rights reserved.
Bahniuk M.S.,University of Alberta
Biointerphases | Year: 2012
Despite its medical applications, the mechanisms responsible for the osseointegration of bioactive glass (45S5) have yet to be fully understood. Evidence suggests that the strongest predictor for osseointegration of bioactive glasses, and ceramics, with bone tissue as the formation of an apatitic calcium phosphate layer atop the implanted material, with osteoblasts being the main mediator for new bone formation. Most have tried to understand the formation of this apatitic calcium phosphate layer, and other bioresponses between the host and bioactive glass 45S5 using Simulated Body Fluid; a solution containing ion concentrations similar to that found in human plasma without the presence of proteins. However, it is likely that cell attachment is probably largely mediated via the adsorbed protein layer. Plasma protein adsorption at the tissue bioactive glass interface has been largely overlooked. Herein, we compare crystalline and amorphous bioactive glass 45S5, in both melt-derived as well as sol-gel forms. Thus, allowing for a detailed understanding of both the role of crystallinity and powder morphology on surface ions, and plasma protein adsorption. It was found that sol-gel 45S5 powders, regardless of crystallinity, adsorbed 3-5 times as much protein as the crystalline melt-derived counterpart, as well as a greater variety of plasma proteins. The devitrification of melt-cast 45S5 resulted in only small differences in the amount and variety of the adsorbed proteome. Surface properties, and not material crystallinity, play a role in directing protein adsorption phenomena for bioactive glasses given the differences found between crystalline melt-cast 45S5 and sol-gel derived 45S5.
Fairchild A.,University of Alberta
Current Opinion in Supportive and Palliative Care | Year: 2010
Prospective study of barriers to both delivery and receipt of adequate pain management is needed, as the majority of published literature is based on survey studies. Treatment must be individualized based on clinical circumstances and patient wishes, with the goal of maximizing function and quality of life. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Lowary T.L.,University of Alberta
Accounts of Chemical Research | Year: 2016
ConspectusThe cell surface (or cell wall) of bacteria is coated with carbohydrate (or glycan) structures that play a number of important roles. These include providing structural integrity, serving as a permeability barrier to extracellular compounds (e.g., drugs) and modulating the immune system of the host. Of interest to this Account is the cell wall structure of mycobacteria. There are a host of different mycobacterial species, some of which cause human disease. The most well-known is Mycobacterium tuberculosis, the causative agent of tuberculosis. The mycobacterial cell wall is characterized by the presence of unusual carbohydrate structures that fulfill the roles described above. However, in many cases, a molecular-level understanding of how mycobacterial cell wall glycans mediate these processes is lacking.Inspired by a seminar he heard as a postdoctoral fellow, the author began his independent research program with a focus on the chemical synthesis of mycobacterial glycans. The goals were not only to develop synthetic approaches to these unique structures but also to provide molecules that could be used to probe their biological function. Initial work addressed the preparation of fragments of two key polysaccharides, arabinogalactan and lipoarabinomannan, which contain large numbers of sugar residues in the furanose (five-membered) ring form. At the time these investigations began, there were few methods reported for the synthesis of oligosaccharides containing furanose rings. Thus, early in the program, a major area of interest was methodology development, particularly for the preparation of 1,2-cis-furanosides. To solve this challenge, a range of conformationally restricted donors have been developed, both in the author's group and others, which provide 1,2-cis-furanosidic linkages with high stereoselectivity.These investigations were followed by application of the developed methods to the synthesis of a range of target molecules containing arabinofuranose and galactofuranose residues. These molecules have now found application in biochemical, immunological, and structural biology investigations, which have shed light on their biosynthesis and how these motifs are recognized by both the innate and adaptive immune systems.More recently, attention has been directed toward the synthesis of another class of immunologically active mycobacterial cell wall glycans, the extractable glycolipids. In this case, efforts have been primarily on phenolic glycolipids, and the compounds synthesized have been used to evaluate their ability to modulate cytokine release. Over the past 20 years, the use of chemical synthesis to provide increasingly complex glycan structures has provided significant benefit to the burgeoning field of mycobacterial glycobiology. Through the efforts of groups from around the globe, access to these compounds is now possible via relatively straightforward methods. As the pool of mycobacterial glycans continues to grow, so too will our understanding of their role in disease, which will undoubtedly lead to new strategies to prevent or treat mycobacterial infections. © 2016 American Chemical Society.
Hsu C.Y.,University of Alberta
Nature protocols | Year: 2012
This protocol outlines steps for optimizing the transfection of adherent primary mammalian cells using the readily available off-the-shelf cationic polymer, 25-kDa branched polyethylenimine (bPEI25). Transfection efficiency of cationic polymers varies among cell lines and is highly dependent on the conditions and environment in which complexes are formed. Factors requiring optimization include the salt concentration, volume, incubation time, mixing order and ratio of polymer to DNA. In this transfection protocol, complexes are prepared in 30 min, with analysis 24 h later; thus, experiments can be completed in 2 d. In this protocol, as an example, we describe the parameters we have optimized for the transfection of bone marrow stromal cells and normal human foreskin fibroblasts. By using this protocol, we have obtained transfection efficiencies comparable to lipofection. An appropriately optimized protocol enhances the utility of cationic polymers in transfecting mammalian cells, thereby providing an effective alternative to expensive commercial reagents.
Kutty S.,University of Nebraska at Omaha |
Smallhorn J.F.,University of Alberta
Journal of the American Society of Echocardiography | Year: 2012
Atrioventricular septal defects comprise a disease spectrum characterized by deficient atrioventricular septation, with several common features seen in all affected hearts and variability in atrioventricular valve morphology and interatrial and interventricular communications. Atrioventricular septal defects are among the more common defects encountered by pediatric cardiologists and echocardiographers. Despite advances in understanding, standard two-dimensional echocardiography may not be the optimal method for the morphologic and functional evaluation of this lesion, particularly malformations of the atrioventricular valve(s). In this review, the authors summarize the role of three-dimensional echocardiography in the diagnostic evaluation of atrioventricular septal defects.
Ru C.Q.,University of Alberta
Applied Physics Letters | Year: 2013
A simplified model is proposed to calculate reduced self-attractive energy of a free monolayer graphene sheet due to ripples. The model admits stable periodic ripple mode of a free-standing graphene ribbon in the absence of a substrate or mechanical stress, and the predicted wavelengths are in robust agreement with observed values. The predicted minimum value of tensile force for eliminating ripples is consistent with related data reported in literature. These results suggest that even the self-attractive energy alone could be strong enough to drive ripple formation. This gives an alternative explanation for ripple formation of free graphene sheets. © 2013 AIP Publishing LLC.
Davison S.N.,University of Alberta
Seminars in Dialysis | Year: 2012
Poor communication and failure to establish goals of care result in unnecessary admissions to hospital, invasive procedures, suffering, and prolongation of the dying process for many CKD patients. Comprehensive CKD care requires systematic integration of advance care planning (ACP). This report describes an approach to ACP for patients with CKD, discusses essential aspects of how to facilitate these conversations, and briefly reviews the empirical evidence supporting the value of ACP. © 2012 Wiley Periodicals, Inc.
Joosse P.,University of Alberta
Terrorism and Political Violence | Year: 2015
“Leaderless resistance” and “lone wolf terrorism” are concepts that have steadily gained importance in the study of oppositional subcultures and terrorist groups, being used to describe the operational realities of a variety of terrorisms, from groups like Al Qaeda to Anders Breivik. In this article, I seek to describe leaderless resistance as a rhetorical construct, a meaning-conferring “ideology of effervescence” that lifts the spirits of both movement progenitors who advocate the strategy as well as incipient lone wolves who consider responding to their exhortations. Through an examination of the case of Wiebo Ludwig and the EnCana pipeline bombings of 2008–2009, I show how these rhetorics emerge in the interactions between activists and their political enemies. With this conception, we can (a) understand more fully the discursive/rhetorical dynamics involved in asymmetrical struggle, (b) problematize the acceptance of the organizational reality of leaderless resistance in the terrorism literature, and (c) question the assertion of some terrorism scholarship that refers to leaderless resistance and other ideologies of effervescence as hallmarks of the “new terrorism.” © 2015 Copyright Taylor & Francis Group, LLC
Rivard E.,University of Alberta
Dalton Transactions | Year: 2014
This Perspective article summarizes recent progress from our laboratory in the isolation of reactive main group species using a general donor-acceptor protocol. A highlight of this program is the use of carbon-based donors in combination with suitable Lewis acidic acceptors to yield stable complexes of parent Group 14 element hydrides (e.g. GeH2 and H 2SiGeH2). It is anticipated that this strategy could be extended to include new synthetic targets from throughout the Periodic Table with possible applications in bottom-up materials synthesis and main group element catalysis envisioned. © 2014 the Partner Organisations.
Alexander M.E.,University of Alberta |
International Journal of Wildland Fire | Year: 2013
This paper constitutes a digest and critique of the currently available information pertaining to the influence of live fuel or foliar moisture content (FMC) on the spread rate of crown fires in conifer forests and shrublands. We review and discuss the findings from laboratory experiments and field-based fire behaviour studies. Laboratory experimentation with single needles or leaves and small conifer trees has shown an unequivocal effect of FMC on flammability metrics. A much less discernible effect of FMC on crown fire rate of spread was found in the existing set of experimental crown fires carried out in conifer forests and similarly with the far more robust database of experimental fires conducted in shrubland fuel complexes. The high convective and radiant heat fluxes associated with these fires and the lack of appropriate experimental design may have served to mask any effect of FMC or live fuel moisture on the resulting spread rate. Four theoretical functions and one empirical function used to adjust rate of fire spread for the effect of foliar or live fuel moisture were also concurrently examined for their validity over a wide range of FMC conditions with varying outcomes and relevancy. None of these model functions was found suitable for use with respect to dead canopy foliage. © 2013 IAWF.
Genuis S.K.,University of Alberta
Journal of the American Society for Information Science and Technology | Year: 2012
Focusing on information behavior in a context where medical evidence is explicitly evolving (management of the menopause transition), this investigation explored how women interact with and make sense of uncertain health information mediated by formal and informal sources. Based on interviews with 28 information seekers and 12 health professionals (HPs), findings demonstrate that participants accessed and valued a wide range of information sources, moved fluidly between formal and informal sources, and trust was strengthened through interaction and referral between sources. Participants were motivated to seek information to prepare for formal encounters with HPs, evaluate and/or supplement information already gathered, establish that they were "normal," understand and address the physical embodiment of their experiences, and prepare for future information needs. Findings revealed four strategies used to construct sense from health information mediated by the many information sources encountered and accessed on an everyday basis: women assumed analytic and experiential "postures"; they valued social contexts for learning and knowledge construction; information consistency was used as a heuristic representing accuracy and credibility; and an important feature of sense making was source complementarity. Implications for health information literacy and patient education are discussed. © 2012 ASIS&T.
Van Manen M.,University of Alberta
Qualitative Health Research | Year: 2012
Some hospital practices that are routine for hospital staff may carry unintended significance for patients and their families. The transfer of neonatal infants between hospitals and hospital environments is one such practice that may be covered by perfectly acceptable rules and regulations but that, at times, gives rise to unsuspected anxieties, pain, and worries in the parent. In this phenomenological study, I explored meaning aspects of the phenomenon transfer to reveal a lived experience of carrying-a carrying across from here to there; a carrying between changing places; a carrying contact of parent-child in-touchness that is enabled or compromised in this experience; a carrying with care; and a carrying as a search for place as home. The concluding recommendations speak to the need for understanding the experiences of hospitalized babies' parents, and speak to the tactful sensitivities required of the health care team during the transfer of child and family. © SAGE Publications 2012.
Gammon D.B.,University of Alberta
PLoS pathogens | Year: 2010
Ribonucleotide reductases (RRs) are evolutionarily-conserved enzymes that catalyze the rate-limiting step during dNTP synthesis in mammals. RR consists of both large (R1) and small (R2) subunits, which are both required for catalysis by the R1(2)R2(2) heterotetrameric complex. Poxviruses also encode RR proteins, but while the Orthopoxviruses infecting humans [e.g. vaccinia (VACV), variola, cowpox, and monkeypox viruses] encode both R1 and R2 subunits, the vast majority of Chordopoxviruses encode only R2 subunits. Using plaque morphology, growth curve, and mouse model studies, we investigated the requirement of VACV R1 (I4) and R2 (F4) subunits for replication and pathogenesis using a panel of mutant viruses in which one or more viral RR genes had been inactivated. Surprisingly, VACV F4, but not I4, was required for efficient replication in culture and virulence in mice. The growth defects of VACV strains lacking F4 could be complemented by genes encoding other Chordopoxvirus R2 subunits, suggesting conservation of function between poxvirus R2 proteins. Expression of F4 proteins encoding a point mutation predicted to inactivate RR activity but still allow for interaction with R1 subunits, caused a dominant negative phenotype in growth experiments in the presence or absence of I4. Co-immunoprecipitation studies showed that F4 (as well as other Chordopoxvirus R2 subunits) form hybrid complexes with cellular R1 subunits. Mutant F4 proteins that are unable to interact with host R1 subunits failed to rescue the replication defect of strains lacking F4, suggesting that F4-host R1 complex formation is critical for VACV replication. Our results suggest that poxvirus R2 subunits form functional complexes with host R1 subunits to provide sufficient dNTPs for viral replication. Our results also suggest that R2-deficient poxviruses may be selective oncolytic agents and our bioinformatic analyses provide insights into how poxvirus nucleotide metabolism proteins may have influenced the base composition of these pathogens.
Sunasee R.,Brandon University |
Narain R.,University of Alberta
Macromolecular Bioscience | Year: 2013
With advances in polymerization techniques as well as selective chemical modification of carbohydrates, glycopolymers and glyco-nanoparticles are emerging as an important class of materials with tailored properties or novel nanotechnology-based platforms for a number of applications. The field of the so-called glyco-nanotechnology is starting to show some promises for future clinical applications. Glyco-nanoparticles, due to their versatile nature, could offer a platform for the design of carbohydrate-based vaccines and possibly allow the development of new single-dose vaccines in disease areas of unmet need. This paper surveys the emerging roles of carbohydrate-based polymeric and nanomaterials for biomolecular recognition processes and vaccine development. The emerging roles of carbohydrate-based polymeric and nanomaterials for biomolecular recognition processes and vaccine development are described. These nanosize materials with well-defined structures and high biocompatibility are demonstrated to be of significant interest in many biological processes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Zecchin M.,National Institute of Oceanography and Applied Geophysics - OGS |
Catuneanu O.,University of Alberta
Marine and Petroleum Geology | Year: 2013
The high-resolution sequence stratigraphy tackles scales of observation that typically fall below the resolution of seismic exploration methods, commonly referred to as of 4th-order or lower rank. Outcrop- and core-based studies are aimed at recognizing features at these scales, and represent the basis for high-resolution sequence stratigraphy. Such studies adopt the most practical ways to subdivide the stratigraphic record, and take into account stratigraphic surfaces with physical attributes that may only be detectable at outcrop scale. The resolution offered by exposed strata typically allows the identification of a wider array of surfaces as compared to those recognizable at the seismic scale, which permits an accurate and more detailed description of cyclic successions in the rock record. These surfaces can be classified as 'sequence stratigraphic', if they serve as systems tract boundaries, or as facies contacts, if they develop within systems tracts. Both sequence stratigraphic surfaces and facies contacts are important in high-resolution studies; however, the workflow of sequence stratigraphic analysis requires the identification of sequence stratigraphic surfaces first, followed by the placement of facies contacts within the framework of systems tracts and bounding sequence stratigraphic surfaces.Several types of stratigraphic units may be defined, from architectural units bounded by the two nearest non-cryptic stratigraphic surfaces to systems tracts and sequences. The need for other types of stratigraphic units in high-resolution studies, such as parasequences and small-scale cycles, may be replaced by the usage of high-frequency sequences. The sequence boundaries that may be employed in high-resolution sequence stratigraphy are represented by the same types of surfaces that are used traditionally in larger scale studies, but at a correspondingly lower hierarchical level. © 2012 Elsevier Ltd.
Catuneanu O.,University of Alberta |
Zecchin M.,National Institute of Oceanography and Applied Geophysics - OGS
Marine and Petroleum Geology | Year: 2013
Both allogenic and autogenic processes may contribute to the formation of sequence stratigraphic surfaces, particularly at the scale of fourth-order and lower rank cycles. This is the case with all surfaces that are associated with transgression, which include the maximum regressive surface, the transgressive ravinement surfaces and the maximum flooding surface, and, under particular circumstances, the subaerial unconformity as well. Not all autogenic processes play a role in the formation of sequence stratigraphic surfaces, but only those that can influence the direction of shoreline shift. Any changes in shoreline trajectory, whether autogenic or allogenic in origin, influence the stratal stacking patterns in the rock record which sequence stratigraphic interpretations are based upon.The discrimination between the allogenic and autogenic processes that may control changes in shoreline trajectory is a matter of interpretation and is tentative at best in many instances. For this reason, the definition and nomenclature of units and bounding surfaces need to be based on the observation of stratal features and stacking patterns rather than the interpretation of the controlling mechanisms. In this light, we extend the concept of 'sequence' to include all cycles bounded by recurring surfaces of sequence stratigraphic significance, irrespective of the origin of these surfaces. The updated sequence concept promotes a separation between the objective observation of field criteria and the subsequent interpretation of controlling parameters, and stresses that a sequence stratigraphic unit is defined by its bounding surfaces and not by its interpreted origin. The use of high-frequency sequences eliminates the need to employ the concepts of parasequence or small-scale cycle in high-resolution studies, and simplifies the sequence stratigraphic methodology and the nomenclature. © 2012 Elsevier Ltd.
Genuis S.K.,University of Alberta
Qualitative Health Research | Year: 2013
In this article I use Social Positioning Theory to explore the experiences of women as they interact with and make sense of evolving health information mediated by formal and informal sources. I investigate how women position themselves within their accounts of information seeking, and the influence of positioning on interactions with health professionals (HPs). Interviewed women gathered and valued information from a range of sources, and were likely to position themselves as autonomous, rather than collaborative or dependent. Faced with evolving health information, women felt responsible not only for information seeking, but also for making sense of gathered and encountered information. Participants did, however, value information provided by HPs and were likely to view decision making as collaborative when HPs fostered information exchange, appeared to appreciate different types of knowledge and cognitive authority, and supported women in their quests for information. Implications for shared decision making are discussed. © The Author(s) 2012.
Yamamoto Y.,University of Alberta
Early human development | Year: 2012
Fetal ventricular outflow tract obstruction (OTO) is congenital heart disease with significant potential for progression before birth as a consequence of the unique nature of the fetal circulation. The pattern of evolution depends upon the timing of development, severity of obstruction and the influence of the OTO on the fetal atrioventricular valve and myocardial function. Critical aortic (AS) or pulmonary (PS) valve stenosis, the two most common forms of fetal OTO, may be associated with progressive ventricular and great artery hypoplasia if presenting early in gestation or with normal ventricular and great artery growth if evolving later in gestation. In some affected fetuses, AS or PS may lead to the evolution of fetal heart failure. This article will review our current understanding of the natural history of fetal AS and PS, experience with fetal intervention and future directions of research. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Tonelli M.A.,University of Alberta |
Wanner C.,University of Wurzburg
Kidney International Supplements | Year: 2013
The 2013 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Lipid Management in Chronic Kidney Disease (CKD) provides guidance on lipid management and treatment for all patients with CKD (non-dialysis-dependent, dialysis-dependent, kidney transplant recipients and children). This guideline contains chapters on the assessment of lipid status and treatment for dyslipidemia in adults and children. Development of the guideline followed an explicit process of evidence review and appraisal. Treatment approaches are addressed in each chapter and guideline recommendations are based on systematic reviews of relevant trials. Appraisal of the quality of the evidence and the strength of recommendations followed the GRADE approach. Ongoing areas of controversies and limitations of the evidence are discussed and additional suggestions are also provided for future research. © 2013 KDIGO.
Caulfield T.,University of Alberta |
McGuire A.L.,Baylor College of Medicine
Annual Review of Medicine | Year: 2012
Direct-to-consumer (DTC) genetic testing has attracted a great amount of attention from policy makers, the scientific community, professional groups, and the media. Although it is unclear what the public demand is for these services, there does appear to be public interest in personal genetic risk information. As a result, many commentators have raised a variety of social, ethical, and regulatory issues associated with this emerging industry, including privacy issues, ensuring that DTC companies provide accurate information about the risks and limitations of their services, the possible adverse impact of DTC genetic testing on healthcare systems, and concern about how individuals may interpret and react to genetic risk information. © 2012 by Annual Reviews. All rights reserved.
Nostbakken L.,University of Alberta
Land Economics | Year: 2012
I analyze drivers of investment in a fishery with tradable quotas. Theory predicts that tradable quotas increase efficiency because efficient firms buy quotas from less efficient firms. I identify what drives investment, using data on Norwegian purse seiners. Results show that while the basic economic investment model explains investment within firms, it does not explain differences between firms. These differences are explained by other firm-specific factors such as geographical location, whether it is a family firm, and prices paid for quotas. Consequently, investment strategies are not necessarily driven by efficiency considerations, and quota trade may not increase allocative efficiency. © 2012 by the Board of Regents of the University of Wisconsin System.
Sim V.L.,University of Alberta
Infectious Disorders - Drug Targets | Year: 2012
Prion diseases, also known as transmissible spongiform encephalopathies, are invariably fatal neurodegenerative diseases for which there are no efficacious treatments. Thousands of compounds have been screened for anti-prion effect, and yet of those that have effect in vitro, very few show effect in vivo, especially if administered in the later stages of disease. However, with new techniques for early diagnosis being developed, and with further insight into the pathogenesis of early disease, including the role of oligomers and the contribution of accessory molecules and signalling cascades, the chance of finding a therapeutic strategy is increasing. Beyond clinical therapy, there is increasing need to find effective decontaminants for blood supplies, as variant Creutzfeldt Jakob Disease (vCJD) is transmissible by blood. Non-toxic preventative therapies are also needed, with ongoing cases of Bovine Spongiform Encephalopathy (BSE) and the spread of Chronic Wasting Disease (CWD) being a growing concern. A primary target for therapy has been the conversion of the normal form of prion protein (PrP C) to its abnormal counterpart (PrP Sc). Many of the chemotherapeutic agents with antiprion effect share structural similarities, often being polyanionic or polycyclic. They may directly bind PrP C or PrP Sc, or they may redistribute, sequester, or down-regulate PrP C, thus preventing its conversion. There have also been some novel approaches, including trapping PrP Sc in a multimeric form such that it can no longer cause conversion, increasing clearance of PrP Sc, targeting accessory molecules which play a role in conversion, targeting pathways which lead to neurodegeneration, and stem cell therapy. It may be that a combination of compounds will be necessary for maximal effect and there is evidence that synergistic responses occur with dual therapy. This updated review focuses primarily on chemicalbased treatments in light of developments in diagnostic technologies, including results from recent clinical trials, and proposes some promising new targets for prion therapy. © 2012 Bentham Science Publishers.
Alexander M.E.,University of Alberta |
Environmental Modelling and Software | Year: 2013
Evaluation is a crucial component for model credibility and acceptance by researchers and resource managers. The nature and characteristics of free-burning wildland fires pose challenges to acquiring the kind of quality data necessary for adequate fire behaviour model evaluation. As a result, in some circles it has led to a research culture that tends to avoid evaluating model performance. Operational fire modelling systems commonly used in western North America have been shown to exhibit an underprediction bias when employed to determine the threshold conditions necessary for the onset of crowning and the associated spread rate of active crown fires in conifer forest stands. This pronouncement was made a few years ago after at least a decade of model misapplication in fire and fuel management simulation modelling stemming from a lack of model evaluation. There are signs that the same situation may be repeated with developing physics-based models that simulate potential wildland fire behaviour; these models have as yet undergone limited testing against observations garnered from planned and/or accidental wildland fires. We propose a broad co-operative project encompassing modellers and experimentalists is needed to define and acquire the benchmark fire behaviour data required for model calibration and evaluation. © 2012 Elsevier Ltd.
Bergren A.J.,Canadian National Institute For Nanotechnology |
McCreery R.L.,University of Alberta
Annual Review of Analytical Chemistry | Year: 2011
This review discusses the analytical characterization of molecular electronic devices and structures relevant thereto. In particular, we outline the methods for probing molecular junctions, which contain an ensemble of molecules between two contacts. We discuss the analytical methods that aid in the fabrication and characterization of molecular junctions, beginning with the confirmation of the placement of a molecular layer on a conductive or semiconductive substrate. We emphasize methods that provide information about the molecular layer in the junction and outline techniques to ensure molecular layer integrity after the complete fabrication of a device. In addition, we discuss the analytical information derived during the actual device operation. Copyright © 2011 by Annual Reviews. All rights reserved.
Siraki A.G.,University of Alberta
Advances in Molecular Toxicology | Year: 2013
Aromatic amines (also known as arylamines) form a very important class of xenobiotics. The arylamine substructure is found in pesticides, carcinogens, and drugs. It is therefore unsurprising that arylamine drugs possess varying degrees of toxicity which ultimately depend on dose, exposure, and the particular genetic makeup of the individual. Arylamines have been shown to undergo oxidation reactions to produce reactive metabolites. This chapter will focus on a subset of reactive metabolites which are the arylamine-free radical metabolites. A detailed discussion on how these free radical metabolites form is presented, and association between the latter and toxicity reactions are discussed. Particular emphasis is devoted to the subject of arylamine-induced blood dyscrasias and recent advances as well as future prospects in this area. © 2013 Elsevier B.V.
Wu Y.,Tsinghua University |
Zhao R.C.H.,Peking Union Medical College |
Tredget E.E.,University of Alberta
Stem Cells | Year: 2010
Our understanding of the role of bone marrow (BM)-derived cells in cutaneous homeostasis and wound healing had long been limited to the contribution of inflammatory cells. Recent studies, however, suggest that the BM contributes a significant proportion of noninflammatory cells to the skin, which are present primarily in the dermis in fibroblast-like morphology and in the epidermis in a keratinocyte phenotype; and the number of these BM-derived cells increases markedly after wounding. More recently, several studies indicate that mesenchymal stem cells derived from the BM could significantly impact wound healing in diabetic and nondiabetic animals, through cell differentiation and the release of paracrine factors, implying a profound therapeutic potential. This review discusses the most recent understanding of the contribution of BM-derived noninflammatory cells to cutaneous homeostasis and wound healing. © AlphaMed Press.
Casey J.R.,University of Alberta |
Grinstein S.,Cell Biology Program |
Orlowski J.,McGill University
Nature Reviews Molecular Cell Biology | Year: 2010
Protons dictate the charge and structure of macromolecules and are used as energy currency by eukaryotic cells. The unique function of individual organelles therefore depends on the establishment and stringent maintenance of a distinct pH. This, in turn, requires a means to sense the prevailing pH and to respond to deviations from the norm with effective mechanisms to transport, produce or consume proton equivalents. A dynamic, finely tuned balance between proton-extruding and proton-importing processes underlies pH homeostasis not only in the cytosol, but in other cellular compartments as well.
Cole L.K.,University of Alberta
Hepatology (Baltimore, Md.) | Year: 2010
Tamoxifen is an anti-estrogen drug widely used for the treatment of hormone-sensitive breast cancer. Approximately 43% of breast cancer patients treated with tamoxifen develop hepatic steatosis. The mechanism or mechanisms by which tamoxifen may induce lipid accumulation in the liver are unclear. Mice were injected with tamoxifen or vehicle (sesame oil containing 1% benzyl alcohol) for 5 consecutive days. In comparison with the vehicle, tamoxifen increased hepatic triacylglycerol levels by 72%. The levels of plasma triacylglycerol were similar between the tamoxifen-treated and control groups. We found increased radiolabeling of triacylglycerol and phospholipids from [(3)H]acetate (∼50%) but not [(14)C]oleate in hepatocytes from tamoxifen-treated mice versus control mice. Fatty acid uptake, triacylglycerol secretion, and fatty acid oxidation remained unchanged in isolated hepatocytes after tamoxifen treatment. The apparent increase in fatty acid synthesis was explained by a marked decrease in the phosphorylation of acetyl coenzyme A carboxylase, which resulted in its activation. CONCLUSION: Our data suggest that increased de novo fatty acid synthesis is the primary event leading to tamoxifen-induced steatosis in the mouse liver. Inhibition of fatty acid synthesis might, therefore, ameliorate steatosis/steatohepatitis in breast cancer patients treated with tamoxifen.
Lalonde S.V.,French National Center for Scientific Research |
Konhauser K.O.,University of Alberta
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015
The Great Oxidation Event (GOE) is currently viewed as a protracted process during which atmospheric oxygen increased above ∼10-5 times the present atmospheric level (PAL). This threshold represents an estimated upper limit for sulfur isotope mass-independent fractionation (S-MIF), an Archean signature of atmospheric anoxia that begins to disappear from the rock record at 2.45 Ga. However, an increasing number of papers have suggested that the timing for oxidative continental weathering, and by conventional thinking the onset of atmospheric oxygenation, was hundreds of million years earlier than previously thought despite the presence of S-MIF. We suggest that this apparent discrepancy can be resolved by the earliest oxidative-weathering reactions occurring in benthic and soil environments at profound redox disequilibrium with the atmosphere, such as biological soil crusts and freshwater microbial mats covering riverbed, lacustrine, and estuarine sediments. We calculate that oxygenic photosynthesis in these millimeter-thick ecosystems provides sufficient oxidizing equivalents to mobilize sulfate and redox-sensitive trace metals from land to the oceans while the atmosphere itself remained anoxic with its attendant S-MIF signature. As continental freeboard increased significantly between 3.0 and 2.5 Ga, the chemical and isotopic signatures of benthic oxidative weathering would have become more globally significant from a mass-balance perspective. These observations help reconcile evidence for pre-GOE oxidative weathering with the history of atmospheric chemistry, and support the plausible antiquity of a terrestrial biosphere populated by cyanobacteria well before the GOE.
Harvey S.,University of Alberta
Endocrine | Year: 2010
Pituitary somatotrophs secrete growth hormone (GH) into the bloodstream, to act as a hormone at receptor sites in most, if not all, tissues. These endocrine actions of circulating GH are abolished after pituitary ablation or hypophysectomy, indicating its pituitary source. GH gene expression is, however, not confined to the pituitary gland, as it occurs in neural, immune, reproductive, alimentary, and respiratory tissues and in the integumentary, muscular, skeletal, and cardiovascular systems, in which GH may act locally rather than as an endocrine. These actions are likely to be involved in the proliferation and differentiation of cells and tissues prior to the ontogeny of the pituitary gland. They are also likely to complement the endocrine actions of GH and are likely to maintain them after pituitary senescence and the somatopause. Autocrine or paracrine actions of GH are, however, sometimes mediated through different signaling mechanisms to those mediating its endocrine actions and these may promote oncogenesis. Extrapituitary GH may thus be of physiological and pathophysiological significance. © Springer Science+Business Media, LLC 2010.
Kin T.,University of Alberta
Advances in Experimental Medicine and Biology | Year: 2010
Islet transplantation is emerging as a viable treatment option for selected patients with type 1 diabetes. Following the initial report in 2000 from Edmonton of insulin independence in seven out of seven consecutive recipients, there has been a huge expansion in clinical islet transplantation. The challenge we now face is the apparent decline in graft function over time. Isolating high-quality human islets which survive and function for a longer period will no doubt contribute to further improvement in long-term clinical outcome. This chapter reviews the selection of appropriate donors for islet isolation and transplantation, describes each step during islet isolation, and discusses the scope for further improvements. © Springer Science+Business Media B.V. 2010.
Chue P.,University of Alberta |
Lalonde J.K.,Roche Holding AG
Neuropsychiatric Disease and Treatment | Year: 2014
The negative symptoms of schizophrenia represent an impairment of normal emotional responses, thought processes and behaviors, and include blunting or flattening of affect, alogia/aprosody, avolition/apathy, anhedonia, and asociality. Negative symptoms contribute to a reduced quality of life, increased functional disability, increased burden of illness, and poorer long-term outcomes, to a greater degree than positive symptoms. Primary negative symptoms are prominent and persistent in up to 26% of patients with schizophrenia, and they are estimated to occur in up to 58% of outpatients at any given time. Negative symptoms respond less well to medications than positive symptoms, and to date treatment options for negative symptoms have been limited, with no accepted standard treatment. Modest benefits have been reported with a variety of different agents, including second-generation antipsychotics and add-on therapy with antidepressants and other pharmacological classes. Recent clinical research focusing on negative symptoms target novel biological systems, such as glutamatergic neurotransmission. Different approaches include: enhancing N-methyl-D-aspartate receptor function with agents that bind directly to the glycine ligand site or with glycine reuptake inhibitors; influencing the metabotropic glutamate receptor (mGluR2/3) with positive allosteric modulators; and stimulating nicotinic acetylcholine receptors. In conclusion, the lack of clearly efficacious pharmacological treatments for the management of negative symptoms represents a significant unmet need, especially considering the importance of these symptoms on patient outcomes. Hence, further research to identify and characterize novel pharmacological treatments for negative symptoms is greatly needed. © 2014 Chue and Lalonde.
Lowary T.L.,University of Alberta
Current Opinion in Chemical Biology | Year: 2013
Complex glycans participate in many essential life processes. Studies of glycan-mediated biological events have traditionally employed structurally defined fragments of the more elaborate natural molecules. However, it is now clear that this approach may sometimes be insufficient and this realization has prompted a desire to synthesize glycans of similar size and complexity to those found in nature. We highlight here recent work describing the synthesis of such molecules. © 2013 Elsevier Ltd.
Bindels L.B.,Catholic University of Louvain |
Delzenne N.M.,Catholic University of Louvain |
Cani P.D.,Catholic University of Louvain |
Walter J.,University of Alberta
Nature Reviews Gastroenterology and Hepatology | Year: 2015
The essential role of the gut microbiota for health has generated tremendous interest in modulating its composition and metabolic function. One of these strategies is prebiotics, which typically refer to selectively fermented nondigestible food ingredients or substances that specifically support the growth and/or activity of health-promoting bacteria that colonize the gastrointestinal tract. In this Perspective, we argue that advances in our understanding of diet-microbiome-host interactions challenge important aspects of the current concept of prebiotics, and especially the requirement for effects to be 'selective' or 'specific'. We propose to revise this concept in an effort to shift the focus towards ecological and functional features of the microbiota more likely to be relevant for host physiology. This revision would provide a more rational basis for the identification of prebiotic compounds, and a framework by which the therapeutic potential of modulating the gut microbiota could be more fully materialized. © 2015 Macmillan Publishers Limited.
Simen-Kapeu A.,University of Alberta
BMC Public Health | Year: 2010
Background. Overweight in childhood is a major public health concern that calls for immediate preventative action. An increasing number of reports suggest that gender specific approaches to prevention may be more effective. However, there is a paucity of information to guide gender-sensitive health promotion and population health interventions for the prevention of overweight in childhood. In the present study, we sought to determine gender-differentials in overweight and underlying behaviors, nutrition and physical activity, among pre-adolescents in Alberta, Canada, to inform the discussion on gender-focused interventions for chronic disease prevention. Methods. In 2008, we surveyed 3421 grade five students and their parents of 148 randomly selected schools. Students completed the Harvard food frequency questionnaire, questions on physical activities, and had their height and weight measured. Parents completed questions on socio-economic background and child's lifestyle. We applied multilevel regression methods to assess gender differentials in overweight, nutrition and physical activity. Results. Overall, the prevalence of overweight was slightly higher among boys (29.1%) than girls (27.9%) with more pronounced differences in towns and urban geographies. Boys reported to be much more physically active relative to girls (OR = 2.12, 95% CI: 1.73-2.60). Diets of boys, relative to those of girls, reportedly constituted more fat and were less likely to meet the recommendation of 6 daily servings of vegetables and fruits (OR = 0.81, 95% CI: 0.71-0.93). Conclusion. Our findings confirm the existence of gender differences in physical activity and nutrition, and support gender-focused health promotion whereby priority is given to physical activity among girls and to healthy eating among boys. © 2010 Simen-Kapeu and Veugelers; licensee BioMed Central Ltd.
Bourque S.L.,University of Alberta
Hypertension | Year: 2013
Prenatal hypoxia can alter the growth trajectory of the fetus and cause lasting health complications including vascular dysfunction. We hypothesized that offspring that were intrauterine growth restricted (IUGR) because of prenatal hypoxia would exhibit altered vascular endothelin-1 (ET-1) signaling in later life. Isolated mesenteric artery responses to big ET-1 (bET-1) and ET-1 were assessed by using wire myography. Male IUGR offspring had 3-fold greater bET-1-induced vasoconstriction compared with controls (n=7 per group; P<0.001); NO synthase inhibition with L-N(G)-nitro-arginine-methyl ester potentiated bET-1-induced vasoconstriction, albeit this effect was 2-fold greater (P<0.05) in male control compared with IUGR offspring. Vascular responses to bET-1 were similar between female IUGR and control offspring (n=9-11 per group). In the presence of L-N(G)-nitro-arginine-methyl ester, pretreatment with the chymase inhibitor chymostatin, the gelatinase inhibitor GM6001, or the neutral endopeptidase inhibitor thiorphan did not alter responses to bET-1; however, the ET-converting enzyme inhibitor CGS35066 almost completely abolished vascular responses to bET-1 in control and IUGR groups. Systolic blood pressure in IUGR male offspring was more responsive to ET-1 antagonism in vivo compared with controls (-9 versus -4 mm Hg; n=5 per group; P=0.02); no such differences were observed in female offspring (n=5-6 per group). These results demonstrate that vascular ET-1 function is programmed by prenatal hypoxia and provide further insights into the sex differences in the long-term vascular effects of developmental stressors.
Shibata M.C.,University of Alberta
International Journal of Clinical Practice | Year: 2013
The author discusses the significance and potential pitfalls in performing a meta-analysis underscoring the importance of a usual forgotten issue in meta-analysis called clinical heterogeneity. Clinical heterogeneity can mislead results and misinform clinicians. Practical examples from the literature are given, and the results of meta-analyses are compared with the results of subsequent large randomised clinical trials addressing similar questions from a historical and contemporary point of view, highlighting clinical heterogeneity. The contemporary aspect culminates with the presentation of a meta-analysis evaluating myocardial cell regeneration with an emphasis in clinical heterogeneity, helping clinicians to understand the issue and better appraise future meta-analyses. © 2013 John Wiley & Sons Ltd.
AS04-adjuvanted human papillomavirus (HPV) types 16 and 18 vaccine (Cervarix®): A review of its use in the prevention of premalignant cervical lesions and cervical cancer causally related to certain oncogenic HPV types
McKeage K.,Wolters Kluwer |
Romanowski B.,University of Alberta
Drugs | Year: 2011
The AS04-adjuvanted human papillomavirus (HPV) 1618 vaccine (Cervarix®) is a noninfectious recombinant vaccine produced using purified virus-like particles (VLPs) that induce a strong immunogenic response eliciting high levels of anti-L1 VLP antibodies that persist at levels markedly greater than those observed with natural infection. The vaccine adjuvant (AS04) is composed of monophosphoryl-lipid A, which enhances cellular and humoral immune response, adsorbed to aluminium hydroxide. The vaccine is indicated for the prevention of premalignant cervical lesions and cervical cancer causally related to certain oncogenic HPV types in females aged ≥10 years.The AS04-adjuvanted HPV 1618 vaccine administered in a three-dose schedule over 6 months elicits a high immunogenic response and is highly protective against cervical intraepithelial neoplasia and infection causally related to high-risk oncogenic HPV types. In well designed clinical trials in young women aged 1525 years who were HPV 1618 seronegative and DNA negative to 14 HPV high-risk types, high levels of immunogenicity and protection were sustained for follow-up periods of up to 8.4 years. High and persistent immunogenicity against infection with HPV 1618 has also been demonstrated in older and younger females (aged 1055 years) who were seronegative for vaccine HPV types. The AS04-adjuvanted HPV 1618 vaccine elicited a greater immunogenic response than the quadrivalent HPV vaccine in women aged 1845 years who were seronegative and DNA negative for HPV 1618. The AS04-adjuvanted HPV 1618 vaccine confers cross protection against certain non-vaccine, high-risk HPV types. A rapid and strong anamnestic humoral immune response was elicited following a fourth dose of the vaccine. The AS04-adjuvanted HPV 1618 vaccine is generally well tolerated, and pharmacoeconomic analyses have demonstrated the potential for public health benefits and cost effectiveness when vaccination programmes are run in conjunction with screening programmes. Thus, the AS04-adjuvanted HPV 1618 vaccine prevents cervical disease associated with certain oncogenic HPV types, thereby reducing the burden of premalignant cervical lesions and, very likely, cervical cancer. © 2011 Adis Data Information BV. All rights reserved.
Rahman H.,University of Alberta
Canadian Journal of Plant Science | Year: 2013
The need of broadening genetic diversity in spring canola (Brassica napus) breeding programs seems to be the general consensus among canola breeders and researchers. Diversity analysis by the use of molecular markers has identified several B. napus gene pools as well as allied Brassica species that are genetically distinct from spring canola B. napus; and these gene pools can be used for the improvement of this crop. Use of genetically diverse and un-adapted B. napus germplasm in the breeding of spring canola can be challenging, as introduction of several unwanted traits/alleles from exotic germplasm into spring canola occurs, and this would require repeated cycles of breeding for improvement. Similarly, use of allied species can be even more challenging due to the difficulties associated with interspecific hybrid production, sterility of hybrids, linkage drag, and the introduction of unwanted alleles. However, this can be compensated in the long-term perspective for the improvement of this crop. Some research efforts have been made in recent years to broaden allelic diversity in spring canola for the improvement of seed yield and other traits in open-pollinated and hybrid cultivars with promising results. Seed yield is a complex trait which is controlled by several gene loci with multiple alleles at these loci as well as interactions between loci and different alleles. This makes the identification of right allelic combinations an extremely challenging task. However, canola breeders have been able to make steady improvements in this crop in past decades based on the amount of allelic diversity present in existing breeding material. Introduction of favourable new alleles in breeding programs would allow breeders to create superior allelic combinations, enhancing the diversity in current breeding materials to further improve the crop. With the availability of the Brassica genome sequence, knowledge of sequence variation in specific genes and cost-effective high-throughput genotyping, it is expected that molecular plant breeding will play an important role in the breeding of canola cultivars. Discovery of favourable allele combinations in a short span of time is likely to be facilitated through the application of modern breeding tools.
O'Reilly M.,University of Alberta |
Thebaud B.,Ottawa Hospital Research Institute
Seminars in Perinatology | Year: 2013
Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity, which affects very preterm infants. Advances in perinatal care have enabled the survival of infants born as early as 23-24 weeks of gestation, but make the task more challenging of protecting injury to an ever more immature lung. Currently, there is no specific treatment for BPD. Recent advances in our understanding of stem/progenitor cells and their potential to repair damaged organs offer the possibility of cell-based treatments for neonatal lung injury. This review summarizes the recent advances in our understanding of lung stem cells during normal and impaired lung growth and the exciting pre-clinical data using mesenchymal stromal cells to prevent/repair impaired alveolar growth in experimental models of BPD. © 2013 Elsevier Inc.
Pannu N.,University of Alberta
Current Opinion in Nephrology and Hypertension | Year: 2013
Purpose of review: Chronic kidney disease (CKD) remains one of the most potent predictors of acute kidney injury (AKI); however, recent epidemiologic studies have demonstrated a complex interplay between these two clinical entities. A growing body of evidence supports a bidirectional relationship: AKI leads to CKD, and the presence of CKD increases the risk of AKI. Additionally, several studies suggest that the presence of underlying CKD does modify the relation between AKI and adverse outcomes. In this article, we will review recent studies supporting the hypothesis that AKI leads to CKD and will explore the role of CKD as an effect modifier for AKI. Recent findings: A recent meta-analysis confirms the association between AKI and the development of CKD and end-stage renal disease. Patient survival and renal outcomes after AKI are influenced by the presence of underlying CKD. AKI survivors with complete recovery of renal function remain at elevated risk of developing de-novo CKD, which may influence long-term survival; however, recovery of kidney function after AKI is associated with better long-term survival and renal function. Summary: Recent findings support a strong association between AKI and CKD. There is uncertainty as to whether this relationship is causal. CKD is an effect modifier in AKI. Copyright © Lippincott Williams & Wilkins.
Leung K.C.W.,University of Calgary |
Tonelli M.,University of Alberta |
James M.T.,University of Calgary
Nature Reviews Nephrology | Year: 2013
In the past two decades, a substantial increase in the incidence of acute kidney injury (AKI) and kidney injury requiring dialysis has occurred in North America. This increase has coincided with an increase in the incidence of end-stage renal disease (ESRD), which has exceeded that expected based upon the prevalence of chronic kidney disease (CKD). In order to better understand the association between these conditions, there has been a proliferation of studies that have examined the risks of incident and progressive CKD following AKI. Animal studies have shown that failed differentiation of epithelial cells following renal ischaemia-reperfusion injury might lead to tubulointerstitial fibrosis, supporting a biological mechanism linking AKI and CKD. Strong and consistent associations between AKI and incident CKD, progression of CKD and incident ESRD have also been shown in epidemiological studies. In this Review, we summarize the wealth of available data on the relationship between AKI and CKD, and discuss the implications of these findings for the long-term clinical management of patients following AKI. We also identify areas of active investigation and future directions for research.
Jing Y.,University of Alberta
IEEE Transactions on Wireless Communications | Year: 2010
Distributed space-time coding (DSTC) is a cooperative scheme for wireless relay networks that achieves full diversity without channel information at the relays. In this paper, the use of maximum-ratio combining (MRC) at multiple-antenna relays in combination with DSTC is proposed. Simulation and theoretical analysis show that the new scheme outperforms the original DSTC. In some network scenarios, it can even improve the scaling of the error rate with the transmit power. Furthermore, the proposed scheme requires a shorter training interval than DSTC. © 2010 IEEE.
Derksen J.J.,University of Alberta
Computers and Fluids | Year: 2010
Cross flow phenomena between connected sub-channels are studied by means of numerical simulations based on lattice-Boltzmann discretization. The cross (that is lateral) transfer is largely due to macroscopic instabilities developing at two shear layers. The characteristic size and advection velocity of the instabilities favorably compare with experimental results from the literature on a geometrically similar system. The strength of the cross flow strongly depends on the Reynolds number, with cross flow developing only for Reynolds numbers (based on macroscopic flow quantities) larger than 1360. Mass transfer between the sub-channels has been assessed by adding a passive scalar to the flow and solving its transport equation. As a result of the intimate connection of cross flow and lateral mass transfer, also the mass transfer coefficient is a pronounced function of Re. © 2010 Elsevier Ltd.
Li J.,University of Alberta
Catheterization and Cardiovascular Interventions | Year: 2013
Oxygen consumption (VO2) is an important part of hemodynamics using the direct Fick principle in children undergoing cardiac catheterization. Accurate measurement of VO2 is vital. Obviously, any error in the measurement of VO2 will translate directly into an equivalent percentage under- or overestimation of blood flows and vascular resistances. It remains common practice to estimate VO2 values from published predictive equations. Among these, the LaFarge equation is the most commonly used equation and gives the closest estimation with the least bias and limits of agreement. However, considerable errors are introduced by the LaFarge equation, particularly in children younger than 3 years of age. Respiratory mass spectrometry remains the "state-of-the-art" method, allowing highly sensitive, rapid and simultaneous measurement of multiple gas fractions. The AMIS 2000 quadrupole respiratory mass spectrometer system has been adapted to measure VO2 in children under mechanical ventilation with pediatric ventilators during cardiac catheterization. The small sampling rate, fast response time and long tubes make the equipment a unique and powerful tool for bedside continuous measurement of VO2 in cardiac catheterization for both clinical and research purposes. © 2012 Wiley Periodicals, Inc.
Craven M.A.,McMaster University |
Bland R.,University of Alberta
Canadian Journal of Psychiatry | Year: 2013
Objectives: To describe the current state of knowledge about detection and treatment of major depressive disorder (MDD) by family physicians (FPs), and to identify gaps in practice and current and future challenges. Methods: We reviewed the recent literature on MDD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, or International Classification of Diseases, Revision 10) in primary care, with an emphasis on systematic reviews and meta-analyses addressing prevalence, the impact of an aging population and of chronic disease on MDD rates in primary care, detection and treatment rates by FPs, adequacy of treatment, and interventions that could improve recognition and treatment. Results: About 10% of primary care patients are likely to meet criteria for MDD. The number of cases will increase as the baby boomer cohort ages and as the prevalence of chronic disease increases. The bidirectional relation between MDD and chronic disease is now firmly established. Detection and treatment rates in primary care remain low. Treatment quality is frequently inadequate in terms of follow-up and monitoring. Formal case management and collaborative care interventions are likely to provide some benefits. Conclusions: Low detection rates and low treatment rates need to be addressed. Planned reassessment may improve detection rates when the FP is uncertain whether MDD is present, but further research is needed to determine why FPs frequently do not initiate treatment, even when MDD is detected. A caring, attentive FP who monitors depressed patients is likely to have considerable placebo effect. Greater focus on integrated, concurrent treatment for MDD and chronic physical diseases in the middle-aged and elderly is also required.
Sellman D.,University of Alberta
Medicine, Health Care and Philosophy | Year: 2011
The values of nursing arise from a concern with human flourishing. If the desire to become a nurse is a reflection of an aspiration to care for others in need then we should anticipate that those who choose to nurse have a tendency towards the values we would normally associate with a caring profession (care, compassion, perhaps altruism, and so on). However, these values require a secure base if they are not to succumb to the corrupting pressures of the increasingly instrumental nature of the values of the institutions in which healthcare in general and nursing in particular takes place. One way of securing a base for withstanding the corrupting influences of the institution is to understand nursing as a practice in the sense in which Alasdair MacIntyre uses that term. In this brief paper I will outline ways in which the managerial imperative of meeting targets is both distorting practice and undermining nursing's values. I conclude that understanding nursing as a MacIntyrean practice provides a refuge from what might otherwise be overwhelming pressures for nurses to adopt instrumental values to the detriment of professional caring values. © 2010 Springer Science+Business Media B.V.
Krkosek M.,University of Alberta |
Krkosek M.,University of Washington
Frontiers in Ecology and the Environment | Year: 2010
The spread of sea lice (Lepeophtheirus salmonis) from salmon farms probably contributes to declines of some native Pacific salmon populations. Migration normally protects juvenile wild Pacific salmon from the marine ectoparasite in coastal waters by separating juvenile salmon from infected wild adults that are located offshore. Farmed salmon populations dwarf natural coastal host populations, particularly in winter, leading to biomagnification of louse populations. By spring, there may be large numbers of lice on farmed salmon, and this is associated with recurrent parasite infestations of wild juvenile salmon and depressed wild salmon stocks. Abiotic (eg temperature and salinity), biotic (eg predator abundance and food availability), and management (eg periodically emptying farms and applying chemical parasiticides) factors are thought to mediate the louse threat, but none have been well studied. Policy is needed that protects undeveloped juvenile salmon habitats and that supports long-term study of salmon ecosystems, to evaluate the sustainability of wild and farmed salmon. © The Ecological Society of America.
Derksen J.J.,University of Alberta
Industrial and Engineering Chemistry Research | Year: 2012
Simulations of flow and scalar transport in stirred tanks operated in transitional and mildly turbulent regimes (Re = 3000-12000) are presented. The moderate Reynolds numbers allow the flow to be simulated directly, without the use of turbulence closure or subgrid-scale models. The Newtonian liquids that are blended have different densities and/or viscosities, and the emphasis is on how these differences affect mixing times. The density difference is characterized by a Richardson number (Ri) that varies in the range of 0-0.5. The kinematic viscosity ratio is between 1 and 4. The results show that mixing times increase steeply with increasing Ri and that changing the tank layout can partly mitigate this effect. The viscosity ratio has a much weaker influence on the mixing time. © 2012 American Chemical Society.
Hamann A.,University of Alberta |
Aitken S.N.,University of British Columbia
Diversity and Distributions | Year: 2013
Aim: A number of assumptions underpinning the use of species distribution models to predict biological responses to climate change are violated for temperate and boreal tree species that are widespread, long-lived and genetically adapted to local climate conditions. To address this situation, we propose a methodology to account for the potential effects of genetic structure, adaptive potential and limited migration capacity. Location: British Columbia, Canada. Methods: Similar to the widely used 'no migration' and 'unlimited migration' scenarios, we employ more refined biological response scenarios to evaluate the potential effects of genetic adaptation to local environments and the capacity of species to adapt and migrate. These scenarios are realized by two sets of geographic delineations that partition the species range into multiple populations and that subdivide the study area into smaller landscape units. Results: In a case study for British Columbia, we demonstrate how the approach can be used to evaluate the adequacy of a reserve system of 906 protected areas to ensure long-term maintenance of forest genetic resources for 48 tree species. We find that between 35% and 85% of locally adapted populations in protected areas are maintained under a median climate change scenario until the end of the century. A sensitivity analysis shows that assumptions about migration and adaptation capacity of species have a major effect on the projected conservation status. Main conclusions: We propose that the results of species distribution models have practical value for conservation planning if the focus is on maintenance rather than loss of suitable habitat. Accounting for genetic structure, adaptive potential and migration capacity through best-case and worst-case scenarios provide important information to effectively allocate limited resources available for conservation action. © 2012 Blackwell Publishing Ltd.
Andrin C.,University of Alberta
Nucleus (Austin, Tex.) | Year: 2012
Nuclear actin is involved in several nuclear processes from chromatin remodeling to transcription. Here we examined the requirement for actin polymerization in DNA double-strand break repair. Double-strand breaks are considered the most dangerous type of DNA lesion. Double-strand break repair consists of a complex set of events that are tightly regulated. Failure at any step can have catastrophic consequences such as genomic instability, oncogenesis or cell death. Many proteins involved in this repair process have been identified and their roles characterized. We discovered that some DNA double-strand break repair factors are capable of associating with polymeric actin in vitro and specifically, that purified Ku70/80 interacts with polymerized actin under these conditions. We find that the disruption of polymeric actin inhibits DNA double strand break repair both in vitro and in vivo. Introduction of nuclear targeted mutant actin that cannot polymerize, or the depolymerization of endogenous actin filaments by the addition of cytochalasin D, alters the retention of Ku80 at sites of DNA damage in live cells. Our results suggest that polymeric actin is required for proper DNA double-strand break repair and may function through the stabilization of the Ku heterodimer at the DNA damage site.
Brigandt I.,University of Alberta
Studies in History and Philosophy of Science Part C :Studies in History and Philosophy of Biological and Biomedical Sciences | Year: 2013
The paper discusses how systems biology is working toward complex accounts that integrate explanation in terms of mechanisms and explanation by mathematical models-which some philosophers have viewed as rival models of explanation. Systems biology is an integrative approach, and it strongly relies on mathematical modeling. Philosophical accounts of mechanisms capture integrative in the sense of multilevel and multifield explanations, yet accounts of mechanistic explanation (as the analysis of a whole in terms of its structural parts and their qualitative interactions) have failed to address how a mathematical model could contribute to such explanations. I discuss how mathematical equations can be explanatorily relevant. Several cases from systems biology are discussed to illustrate the interplay between mechanistic research and mathematical modeling, and I point to questions about qualitative phenomena (rather than the explanation of quantitative details), where quantitative models are still indispensable to the explanation. Systems biology shows that a broader philosophical conception of mechanisms is needed, which takes into account functional-dynamical aspects, interaction in complex networks with feedback loops, system-wide functional properties such as distributed functionality and robustness, and a mechanism's ability to respond to perturbations (beyond its actual operation). I offer general conclusions for philosophical accounts of explanation. © 2013 Elsevier Ltd.
Gay-Balmaz F.,Ecole Normale Superieure de Paris |
Putkaradze V.,University of Alberta
Physical Review Letters | Year: 2012
One of the most challenging and basic problems in elastic rod dynamics is a description of rods in contact that prevents any unphysical self-intersections. Most previous works addressed this issue through the introduction of short-range potentials. We study the dynamics of elastic rods with perfect rolling contact which is physically relevant for rods with a rough surface. Such dynamics cannot be described by the introduction of any kind of potential. We show that, surprisingly, the presence of rolling contact in rod dynamics leads to highly complex behavior even for the evolution of small disturbances. © 2012 American Physical Society.
Mohamed Y.A.-R.I.,University of Alberta |
El-Saadany E.F.,University of Waterloo
IEEE Transactions on Energy Conversion | Year: 2011
This paper presents a robust natural-frame-based interfacing scheme for grid-connected distributed generation inverters. The control scheme consists of a dead-beat line-voltage sensorless natural-frame current controller, adaptive neural network (NN)-based disturbance estimator, and robust sensorless synchronization loop. The estimated uncertainty dynamics provide the necessary energy shaping in the inverter control voltage to attenuate grid-voltage disturbances and other voltage disturbances caused by interfacing parameter variation. In addition, the predictive nature of the estimator has the necessary phase advance to compensate for system delays. The self-learning feature of the NN adaptation algorithm allows feasible and easy adaptation design at different grid disturbances and operating conditions. The fact that converter synchronization is based on the fundamental grid-voltage facilitates the use of the estimated uncertainty to extract the position of the fundamental grid-voltage vector without using voltage sensors. Theoretical analysis and comparative evaluation results are presented to demonstrate the effectiveness of the proposed control scheme. © 2011 IEEE.
Lee C.-H.,University of Alberta |
Nucci M.R.,Brigham and Womens Hospital
Histopathology | Year: 2015
Endometrial stromal sarcoma (ESS) is a gynaecological sarcoma that is composed of cells that resemble those of proliferative-phase endometrial stroma. The 2014 World Health Organization tumour classification system separates ESS into low-grade and high-grade types, which are histologically, genetically and clinically distinct from undifferentiated uterine sarcoma (UUS). Low-grade ESSs frequently contain chromosomal rearrangements that result in JAZF1-SUZ12 fusion or equivalent genetic fusions. Although most low-grade ESSs show classic histological features that closely resemble those of proliferative-phase endometrial stroma, there are several histological variants that are associated with the same genetic fusions as seen in the classic type. High-grade ESS is defined by the presence of YWHAE-NUTM2A/B (YWHAE-FAM22A/B) fusions. High-grade ESSs are clinically more aggressive than low-grade ESSs, but are associated with a lower mortality rate than UUSs. The histological and immunophenotypic features of these different types of ESS, and their diagnostic considerations, are the subjects of this review. © 2014 John Wiley & Sons Ltd.
Gosgnach S.,University of Alberta
Integrative and Comparative Biology | Year: 2011
Locomotor behavior in mammals requires a complex pattern of muscle activation. Neural networks, known as central pattern generators (CPGs) and located entirely within the spinal cord, are responsible for generating much of the timing and pattern required for locomotor movements. Historically, identification of interneuronal components of the locomotor CPG in walking mammals has proven troublesome, primarily because of the difficulty in identifying functionally homogeneous groups of neurons in the spinal cord. Recently, a molecular approach has been used to identify populations of genetically similar interneurons based on the expression of transcription factors early in embryonic development. Preliminary work on these cell populations has shown that many comprise essential components of the locomotor CPG. Here I identify populations of genetically-defined interneurons that are candidate "first-order" cells of this neural network, potentially responsible for generating the locomotor rhythm in the mammalian spinal cord. Identification of the cell population(s) responsible for this key function will provide valuable insight into the structure and function of the locomotor CPG and could potentially lay the groundwork for the development of strategies aimed at regenerating motor pathways following injury to the spinal cord. © The Author 2011. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.
Hebblewhite M.,University of Montana |
Merrill E.H.,University of Alberta
Oikos | Year: 2011
Partial migration is widespread in ungulates, yet few studies have assessed demographic mechanisms for how these alternative strategies are maintained in populations. Over the past two decades the number of resident individuals of the Ya Ha Tinda elk herd near Banff National Park has been increasing proportionally despite an overall population decline. We compared demographic rates of migrant and resident elk to test for demographic mechanisms partial migration. We determined adult female survival for 132 elk, pregnancy rates for 150 female elk, and elk calf survival for 79 calves. Population vital rates were combined in Leslie-matrix models to estimate demographic fitness, which we defined as the migration strategy-specific population growth rate. We also tested for differences in factors influencing risk of mortality between migratory strategies for adult females using Cox-proportional hazards regression and time-varying covariates of exposure to forage biomass, wolf predation risk, and group size. Despite higher pregnancy rates and winter calf weights associated with higher forage quality, survival of migrant adult females and calves were lower than resident elk. Resident elk traded high quality food to reduce predation risk by selecting areas close to human activity, and by living in group sizes 20% larger than migrants. Thus, residents experienced higher adult female survival and calf survival, but lower pregnancy and calf weights. Cause-specific mortality of migrants was dominated by wolf and grizzly bear mortality, whereas resident mortality was dominated by human hunting. Demographic differences translated into slightly higher (2-3%), but non-significant, resident population growth rate compared to migrant elk, suggesting demographic balancing between resident strategies during our study. Despite statistical equivalence, our results are also consistent with slow long-term declines in migrants because of high predation because of higher wolf-caused mortality in migrants. These results emphasize that migrants and residents will make different tradeoffs between forage and risk may affect the demographic balance of partially migratory populations, which may explain recent declines in migratory behavior in many ungulate populations around the world. © 2011 The Authors.
Ivanova N.,University of Alberta
Astrophysical Journal | Year: 2011
One of the most important and uncertain stages in binary evolution is the common envelope (CE) event. Significant attention has been devoted in the literature so far to the energy balance expected to determine the outcome during the CE event. However, this question is intrinsically coupled with the problem of what is left from the donor star after the CE and its immediate evolution. In this paper we argue that an important stage has been overlooked: thepost-CE remnant thermal readjustment (TR) phase. We propose a methodology for unambiguously defining the post-CE remnant mass after it has been thermally readjusted, namely, by calling the core boundary the radius in the hydrogen shell corresponding to the local maximum of the sonic velocity. We argue that the important consequences of the TR phase are (1) a change in the energy budget requirement for the CE binaries and (2) a companion spin-up and chemical enrichment, as a result of the mass transfer (MT) that occurs during the remnant TR. More CE binaries are expected to merge. If the companion is a neutron star (NS), it will be mildly recycled during the TR phase. The MT during the TR phase is much stronger than the accretion rate during the CE, and therefore satisfies the condition for hypercritical accretion better. We also argue that the TR phase is responsible for the production of mildly recycled pulsars in double NSs. © 2011. The American Astronomical Society. All rights reserved.
Furlong M.J.,University of Queensland |
Wright D.J.,Imperial College London |
Dosdall L.M.,University of Alberta
Annual Review of Entomology | Year: 2013
Agricultural intensification and greater production of Brassica vegetable and oilseed crops over the past two decades have increased the pest status of the diamondback moth (DBM), Plutella xylostella L., and it is now estimated to cost the world economy US$4-5 billion annually. Our understanding of some fundamental aspects of DBM biology and ecology, particularly host plant relationships, tritrophic interactions, and migration, has improved considerably but knowledge of other aspects, e.g., its global distribution and relative abundance, remains surprisingly limited. Biological control still focuses almost exclusively on a few species of hymenopteran parasitoids. Although these can be remarkably effective, insecticides continue to form the basis of management; their inappropriate use disrupts parasitoids and has resulted in field resistance to all available products. Improved ecological understanding and the availability of a series of highly effective selective insecticides throughout the 1990s provided the basis for sustainable and economically viable integrated pest management (IPM) approaches. However, repeated reversion to scheduled insecticide applications has resulted in resistance to these and more recently introduced compounds and the breakdown of IPM programs. Proven technologies for the sustainable management of DBM currently exist, but overcoming the barriers to their sustained adoption remains an enormous challenge. © 2013 by Annual Reviews. All rights reserved.
Thomson E.L.,University of Alberta
Virulence | Year: 2012
Members of the Burkholderia cepacia complex (Bcc) have recently gained notoriety as significant bacterial pathogens due to their extreme levels of antibiotic resistance, their transmissibility in clinics, their persistence in bacteriostatic solutions, and their intracellular survival capabilities. As pathogens, the Bcc are known to elaborate a number of virulence factors including proteases, lipases and other exoproducts, as well as a number of secretion system associated effectors. Through random and directed mutagenesis studies, we have identified a Bcc gene cluster capable of expressing a toxin that is both hemolytic and required for full Bcc virulence. The Bcc toxin is synthesized via a non-ribosomal peptide synthetase mechanism, and appears to be related to the previously identified antifungal compound burkholdine or occidiofungin. Further testing shows mutations to this gene cluster cause a significant reduction in both hemolysis and Galleria mellonella mortality. Mutation to a glycosyltransferase gene putatively responsible for a structural-functional toxin variant causes only partial reduction in hemolysis. Molecular screening identifies the Bcc species containing this gene cluster, of which several strains produce hemolytic activity.
Hindle A.,University of Alberta
IEEE International Working Conference on Mining Software Repositories | Year: 2012
Power consumption is becoming more and more important with the increased popularity of smart-phones, tablets and laptops. The threat of reducing a customer's battery-life now hangs over the software developer who asks, "will this next change be the one that causes my software to drain a customer's battery?" One solution is to detect power consumption regressions by measuring the power usage of tests, but this is time-consuming and often noisy. An alternative is to rely on software metrics that allow us to estimate the impact that a change might have on power consumption thus relieving the developer from expensive testing. This paper presents a general methodology for investigating the impact of software change on power consumption, we relate power consumption to software changes, and then investigate the impact of static OO software metrics on power consumption. We demonstrated that software change can effect power consumption using the Firefox web-browser and the Azureus/Vuze BitTorrent client. We found evidence of a potential relationship between some software metrics and power consumption. In conclusion, we explored the effect of software change on power consumption on two projects; and we provide an initial investigation on the impact of software metrics on power consumption. © 2012 IEEE.
Luyckx V.A.,University of Alberta |
Brenner B.M.,Harvard University
Journal of the American Society of Nephrology | Year: 2010
Abundant evidence supports the association between low birth weight (LBW) and renal dysfunction in humans. Anatomic measurements of infants, children, and adults show significant inverse correlation between LBW and nephron number. Nephron numbers are also lower in individuals with hypertension compared with normotension among white and Australian Aboriginal populations. The relationship between nephron number and hypertension among black individuals is still unclear, although the high incidence of LBW predicts low nephron number in this population as well. LBW, a surrogate for low nephron number, also associates with increasing BP from childhood to adulthood and increasing risk for chronic kidney disease in later life. Because nephron numbers can be counted only postmortem, surrogate markers such as birth weight, prematurity, adult height, reduced renal size, and glomerulomegaly are potentially useful for risk stratification, for example, during living-donor assessment. Because early postnatal growth also affects subsequent risk for higher BP or reduced renal function, postnatal nutrition, a potentially modifiable factor, in addition to intrauterine effects, has significant influence on long-term cardiovascular and renal health. Copyright © 2010 by the American Society of Nephrology.
VanderPluym J.,University of Alberta
Current Neurology and Neuroscience Reports | Year: 2015
Indomethacin-responsive headaches are a heterogeneous group of primary headache disorders distinguished by their swift and often absolute response to indomethacin. The epidemiology of these conditions is incompletely defined. Traditionally, indomethacin-responsive headaches include a subset of trigeminal autonomic cephalalgias (paroxysmal hemicrania and hemicrania continua), Valsalva-induced headaches (cough headache, exercise headache, and sex headache), primary stabbing headache, and hypnic headache. These headache syndromes differ in extent of response to indomethacin, clinical features, and differential diagnoses. Neuroimaging is recommended to investigate for various organic causes that may mimic these headaches. Case reports of other primary headache disorders that also respond to indomethacin, such as cluster headache, nummular headache, and ophthalmoplegic migraine, have been described. These “novel” indomethacin-responsive headaches beg the question of what headache characteristics are required to qualify a headache as an indomethacin-responsive headache. Furthermore, they challenge the concept of using a therapeutic intervention as a diagnostic criterion. © 2014, Springer Science+Business Media New York.
Jing Y.,University of Alberta |
Shahbazpanahi S.,University of Ontario Institute of Technology
IEEE Transactions on Signal Processing | Year: 2012
This paper deals with optimal joint user power control and relay distributed beamforming for two-way relay networks, where two end-users exchange information through multiple relays, each of which is assumed to have its own power constraint. The problem includes the design of the distributed beamformer at the relays and the power control scheme for the two end-users to optimize the network performance. Considering the overall two-way network performance, we maximize the lower signal-to-noise ratio (SNR) of the two communication links. For single-relay networks, this maximization problem is solved analytically. For multi-relay networks, we propose an iterative numerical algorithm to find the optimal solution. While the complexity of the optimal algorithm is too high for large networks, two sub-optimal algorithms with low complexity are also proposed, which are numerically shown to perform close to the optimal technique. It is also shown via simulation that for two-way networks with both single relay and multiple relays, proper user power control and relay distributed beamforming can significantly improve the network performance, especially when the power constraints of the two end-users in the networks are unbalanced. Our approach also improves the power efficiency of the network largely. © 1991-2012 IEEE.
Dunn C.W.,Brown University |
Leys S.P.,University of Alberta |
Haddock S.H.D.,Monterey Bay Aquarium Research Institute
Trends in Ecology and Evolution | Year: 2015
Animal evolution is often presented as a march toward complexity, with different living animal groups each representing grades of organization that arose through the progressive acquisition of complex traits. There are now many reasons to reject this classical hypothesis. Not only is it incompatible with recent phylogenetic analyses, but it is also an artifact of 'hidden biology', that is, blind spots to complex traits in non-model species. A new hypothesis of animal evolution, where many complex traits have been repeatedly gained and lost, is emerging. As we discuss here, key details of this new model hinge on a better understanding of the Porifera and Ctenophora, which have each been hypothesized to be sister to all other animals, but are poorly studied and often misrepresented. © 2015 Elsevier Ltd.
Elahi S.,University of Alberta
Frontiers in Immunology | Year: 2014
Newborns are exceedingly susceptible to infection. However, very little is known about what governs the immunological differences seen in early life that result in extreme vulnerability to infection, nor how this changes during infancy. Herein, I provide evidence that the reduced ability to mount a protective immune response to pathogens is not due to an inherent immaturity of neonatal immune cells but instead the functions of these immune cells are actively suppressed by CD71+ erythroid cells. Furthermore, the role of CD71+ erythroid cells in host defense against infection is examined. CD71+ erythroid cells are enriched in newborns and have distinctive immunosuppressive properties that leave them vulnerable to infection. Moreover, immature erythroid cells possess exclusive immunomodulatory properties and may play a role in immune ontogeny. In addition to these distinct features, CD71+ erythroid cells impact digestive health by preventing excessive inflammation following the sudden transition from a sterile in utero setting to excessive colonization with commensals in the external environment. Ongoing research in identifying the beneficial and/or detrimental effects of immature erythrocytes on immune responses may serve to enhance protective newborn immune responses to infection and enable better vaccination strategies for the young to be designed. © 2014 Elahi.
Jugdutt B.I.,University of Alberta
Clinical interventions in aging | Year: 2010
Elderly patients (age ≥ 65 years) with hypertension are at high risk for vascular complications, especially when diabetes is present. Antihypertensive drugs that inhibit the renin-angiotensin system have been shown to be effective for controlling blood pressure in adult and elderly patients. Importantly, renin-angiotensin system inhibitors were shown to have benefits beyond their classic cardioprotective and vasculoprotective effects, including reducing the risk of new-onset diabetes and associated cardiovascular effects. The discovery that the renin-angiotensin system inhibitor and angiotensin II type 1 (AT(1)) receptor blocker (ARB), telmisartan, can selectively activate the peroxisome proliferator-activated receptor-γ (PPARγ, an established antidiabetic drug target) provides the unique opportunity to prevent and treat cardiovascular complications in high-risk elderly patients with hypertension and new-onset diabetes. Two large clinical trials, ONTARGET (Ongoing Telmisartan Alone in combination with Ramipril Global Endpoint Trial) and TRANSCEND (Telmisartan Randomized AssessmeNt Study in ACE-I iNtolerant subjects with cardiovascular disease) have assessed the cardioprotective and antidiabetic effects of telmisartan. The collective data suggest that telmisartan is a promising drug for controlling hypertension and reducing vascular risk in high-risk elderly patients with new-onset diabetes.
Truhachev D.,University of Alberta
IEEE Communications Letters | Year: 2012
Communication over a multiple access channel is considered. Each user modulates his signal as a superposition of redundant data streams where interconnection of data bits can be represented by means of a sparse graph. The receiver observes a signal resulting from the coupling of the sparse modulation graphs. Iterative interference cancellation decoding is analyzed. It is proved that spatial graph coupling allows to achieve the AWGN channel capacity with equal power and rate transmissions. © 2012 IEEE.
Magor K.E.,University of Alberta
Developmental and Comparative Immunology | Year: 2011
The role of the duck as the natural host and reservoir of influenza and efforts to vaccinate ducks during recent outbreaks of avian influenza has renewed interest in the duck antibody response. Ducks have unique antibody structures and expression, with consequences for their function. Aspects of immunoglobulin genetics, gene expression, and antibody function will be reviewed in the context of the duck immune response to influenza. Ducks have three immunoglobulin isotypes, IgM, IgA and IgY in translocon arrangement. The order of heavy chain genes in the locus is unusual, IGHM, IGHA and IGHY, with IGHA in inverse transcriptional orientation. IgH and IgL gene rearrangement in ducks involves limited V, (D) and J element recombination and diversity is generated by gene conversion from pseudogenes. IgY, the functional equivalent of IgG, is produced in two secreted forms, a full-length form and one lacking the third and fourth C region domains, which predominates later in the immune response and lacks the biological effector functions of IgG. The unusual features of duck antibodies may contribute to weak antibody responses and the perpetuation of the virus in this animal reservoir. © 2011 Elsevier Ltd.
Shen M.,University of Alberta
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2015
OBJECTIVE—: Aortic aneurysm, focal dilation of the aorta, results from impaired integrity of aortic extracellular matrix (ECM). Matrix metalloproteinases (MMPs) are traditionally known as ECM-degrading enzymes. MMP2 has been associated with aneurysm in patients and in animal models. We investigated the role of MMP2 in thoracic aortic aneurysm using 2 models of aortic remodeling and aneurysm.APPROACH AND RESULTS—: Male 10-week-old MMP2-deficient (MMP2) and wild-type mice received angiotensin II (Ang II, 1.5 mg/kg/day) or saline (Alzet pump) for 4 weeks. Although both genotypes exhibited dilation of the ascending aorta after Ang II infusion, MMP2 mice showed more severe dilation of the thoracic aorta and thoracic aortic aneurysm. The Ang II–induced increase in elastin and collagen (mRNA and protein) was markedly suppressed in MMP2 thoracic aorta and smooth muscle cells, whereas only mRNA levels were reduced in MMP2-Ang II abdominal aorta. Consistent with the absence of MMP2, proteolytic activities were lower in MMP2-Ang II compared with wild-type-Ang II thoracic and abdominal aorta. MMP2-deficiency suppressed the activation of latent transforming growth factor-â and the Smad2/3 pathway in vivo and in vitro. Intriguingly, MMP2 mice were protected against CaCl2-induced thoracic aortic aneurysm, which triggered ECM degradation but not synthesis.CONCLUSIONS—: This study reveals the dual role of MMP2 in ECM degradation, as well as ECM synthesis. Moreover, the greater susceptibility of the thoracic aorta to impaired ECM synthesis, compared with vulnerability of the abdominal aorta to aberrant ECM degradation, provides an insight into the regional susceptibility of the aorta to aneurysm development. © 2015 American Heart Association, Inc.
Burt N.M.,University of Alberta
American Journal of Physical Anthropology | Year: 2013
Rib collagen of 51 juveniles and 11 adult females from the late medieval Fishergate House cemetery site (York, UK) were analyzed using nitrogen and carbon stable isotope ratio analysis to determine the weaning age for this population and to reconstruct diet. The juveniles' ages ranged from fetal to 5-6 years, while the females were of reproductive age. Previous researchers suggested that the children from Fishergate House might have been weaned later than the medieval British norm of 2 years, based on a mortality peak at 4-6 years of age. The results show weaning was complete by 2 years of age, agreeing with previous British weaning studies. The adult female δ15N values have a mean of 11.4‰ ± 1.1‰ and the δ13C values have a mean of -19.4‰ ± 0.4‰. These findings are consistent with previous isotopic studies of female diet in York during this period, though slightly lower. The weaned juvenile nitrogen values were found to be higher than the adult females (12.4‰ ± 1.0‰ for δ15N and -19.7‰ ± 0.5‰ for δ13C), which might indicate a dependence on higher trophic level proteins such as marine fish or pork. Marine fish is considered a high status food and children are considered low-status individuals at this time, making this a particularly interesting finding. Weaning does not appear to coincide with peak mortality, suggesting environment factors may be playing a larger role in child mortality at Fishergate House. Am J Phys Anthropol 152:407-416, 2013. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc.
Tonelli M.,University of Alberta
Kidney International | Year: 2013
This issue of Kidney International includes two important articles about serum phosphorus and its treatment. The article by Cannata-Andía and colleagues describes a rigorous observational study of the association between serum phosphorus level, phosphate binder use, and clinical outcomes including all-cause and cardiovascular mortality. The article by Mehrotra and colleagues addresses the association between serum phosphorus, socioeconomic status, and mortality among participants in the US-based KEEP program. © 2013 International Society of Nephrology.
Wang W.,University of Alberta
Journal of the American Heart Association | Year: 2013
Coronary artery disease leading to myocardial ischemia is the most common cause of heart failure. Apelin (APLN), the endogenous peptide ligand of the APJ receptor, has emerged as a novel regulator of the cardiovascular system. Here we show a critical role of APLN in myocardial infarction (MI) and ischemia-reperfusion (IR) injury in patients and animal models. Myocardial APLN levels were reduced in patients with ischemic heart failure. Loss of APLN increased MI-related mortality, infarct size, and inflammation with drastic reductions in prosurvival pathways resulting in greater systolic dysfunction and heart failure. APLN deficiency decreased vascular sprouting, impaired sprouting of human endothelial progenitor cells, and compromised in vivo myocardial angiogenesis. Lack of APLN enhanced susceptibility to ischemic injury and compromised functional recovery following ex vivo and in vivo IR injury. We designed and synthesized two novel APLN analogues resistant to angiotensin converting enzyme 2 cleavage and identified one analogue, which mimicked the function of APLN, to be markedly protective against ex vivo and in vivo myocardial IR injury linked to greater activation of survival pathways and promotion of angiogenesis. APLN is a critical regulator of the myocardial response to infarction and ischemia and pharmacologically targeting this pathway is feasible and represents a new class of potential therapeutic agents.
Ferrari R.,University of Alberta
Clinical Rheumatology | Year: 2011
The objective of the study was to determine the odds ratio for compliance with referral to an active treatment program according to coping style in a cohort of acute whiplash-injured subjects. Sixty whiplash patients were assessed within 1 week of their collision for their coping styles and were then questioned 3 weeks later to determine if they had complied with a referral for an active treatment program. Coping style was assessed with the Vanderbilt Pain Management Inventory. Adjusting for age, gender, and initial whiplash disability questionnaire scores, the odds ratio for compliance with therapy for subjects who had a low active/high passive coping style was 0.15 (P=0.03) (95% CI, 0.03-0.86) relative to all other coping style patterns, whose odds ratios did not differ from each other. As a secondary outcome, the odds ratio for reporting prescription medication use for subjects who had a low active/high passive coping style was 6.7 (P=0.038) (95% CI, 1.1-40.4). Those whiplash patients who have a low active/high passive coping style are less likely to attend an active exercise-based rehabilitation program and more likely to use prescription medications in the first 3 weeks following injury. Coping style may affect recovery from whiplash injury through issues of compliance with active therapy and increased reliance on prescription medications. © 2011 Clinical Rheumatology.
Derksen J.J.,University of Alberta
Physics of Fluids | Year: 2011
Direct numerical simulations of granular beds consisting of uniformly sized spherical particles being eroded by a shear flow of Newtonian liquid have been performed. The lattice-Boltzmann method has been used for resolving the flow of the interstitial liquid. Fluid and solid dynamics are fully coupled with the particles having finite size and undergoing hard-sphere collisions. Only laminar flow has been considered with particle-based Reynolds numbers in the range 0.02 to 0.6. The parameter range of the simulations covers the transition between static and mobilized beds. The transition occurs for 0.10<θ<0.15 with θ the Shields number. The transition is insensitive of the Reynolds number and the solid-over-liquid density ratio. Incipient bed motion has been interpreted in terms of the probability density functions of the hydrodynamic forces acting on the spheres in the upper layer of the bed. © 2011 American Institute of Physics.
Genuis S.J.,University of Alberta
Clinical Therapeutics | Year: 2013
Background: Escalating numbers of people throughout the world are presenting to primary care physicians, allergists, and immunologists with myriad clinical symptoms after low-level exposure to assorted everyday chemicals such as smoke, perfumes, air fresheners, paints, glues, and other products. This clinical state is referred to by various diagnostic labels, including multiple chemical sensitivity disorder, environmental intolerance, chemical sensitivity (CS), and sensitivity-related illness, and has been the subject of much controversy within the health care community. Objective: The goal of this study was to provide a brief overview of the etiology, pathogenesis, clinical presentation, and management of CS. An evaluation of the medical community's response to this emerging diagnosis was also explored. Methods: This review was prepared by assessing available medical and scientific literature from MEDLINE, as well as by reviewing numerous books, toxicology journals, conference proceedings, government publications, and environmental health periodicals. A primary observation, however, is that there is limited scientific literature available on the issue of CS. The format of a traditional integrated review was chosen because such reviews play a pivotal role in scientific research and professional practice in medical issues with limited primary study and uncharted clinical territory. Results: The sensitization state of CS seems to be initiated by a significant toxic exposure, occurring as a 1-time event, or on surpassing a threshold of toxicity after toxicant accrual from repeated lower-level exposures. Once sensitized through a toxicant-induced loss of tolerance, individuals exposed to inciting triggers such as minute amounts of diverse everyday chemicals may experience various clinical and immune sequelae, sometimes involving lymphocyte, antibody, or cytokine responses. Precautionary avoidance of inciting triggers will prevent symptoms, and desensitization immunotherapy or immune suppression may improve symptoms in some cases. Sustained resolution of the CS state occurs after successful elimination of the accrued body burden of toxicants through natural mechanisms of toxicant bioelimination and/or interventions of clinical detoxification. Despite extensive clinical evidence to support the veracity of this clinical state, many members of the medical community are reluctant to accept this condition as a pathophysiologic disorder. Conclusions: The emerging problem of ubiquitous adverse toxicant exposures in modern society has resulted in escalating numbers of individuals developing a CS disorder. As usual in medical history, iconoclastic ideas and emerging evidence regarding novel disease mechanisms, such as the pathogenesis of CS, have been met with controversy, resistance, and sluggish knowledge translation. © 2013 Elsevier HS Journals, Inc.
Leys S.P.,University of Alberta
Journal of Experimental Biology | Year: 2015
Genomic and transcriptomic analyses show that sponges possess a large repertoire of genes associated with neuronal processes in other animals, but what is the evidence these are used in a coordination or sensory context in sponges? The very different phylogenetic hypotheses under discussion today suggest very different scenarios for the evolution of tissues and coordination systems in early animals. The sponge genomic 'toolkit' either reflects a simple, pre-neural system used to protect the sponge filter or represents the remnants of a more complex signalling system and sponges have lost cell types, tissues and regionalization to suit their current suspensionfeeding habit. Comparative transcriptome data can be informative but need to be assessed in the context of knowledge of sponge tissue structure and physiology. Here, I examine the elements of the sponge neural toolkit including sensory cells, conduction pathways, signalling molecules and the ionic basis of signalling. The elements described do not fit the scheme of a loss of sophistication, but seem rather to reflect an early specialization for suspension feeding, which fits with the presumed ecological framework in which the first animals evolved. © 2015. Published by The Company of Biologists Ltd.
Davis F.G.,University of Alberta
Annals of Epidemiology | Year: 2013
In the past, mentoring was the job of one senior researcher in which the mentor molded the mentee in his/her own image. With public health being a very multidisciplinary field, mentoring may need to evolve to facilitate the needs of emerging scientists-including epidemiologists. The mentoring relationship can begin at many education stages, including high school. Involving students at all education levels acts as a way to recruit and nurture interest in public health. On the basis of the experience in the medical sciences, mentoring programs also can be used to recruit and retain high-quality professionals in our discipline. Mentoring functions nurture a young mentee with the bonus of greater workplace satisfaction for the mentor. Nevertheless, more understanding of what constitutes successful mentoring and how to develop programs that create great mentors is needed. © 2013 Elsevier Inc.
Boruff J.T.,McGill University |
Storie D.,University of Alberta
Journal of the Medical Library Association | Year: 2014
Objectives: The research investigated the extent to which students, residents, and faculty members in Canadian medical faculties use mobile devices, such as smartphones (e.g., iPhone, Android, Blackberry) and tablet computers (e.g., iPad), to answer clinical questions and find medical information. The results of this study will inform how health libraries can effectively support mobile technology and collections. Methods: An electronic survey was distributed by medical librarians at four Canadian universities to medical students, residents, and faculty members via departmental email discussion lists, personal contacts, and relevant websites. It investigated the types of information sought, facilitators to mobile device use in medical information seeking, barriers to access, support needs, familiarity with institutionally licensed resources, and most frequently used resources. Results: The survey of 1,210 respondents indicated widespread use of smartphones and tablets in clinical settings in 4 Canadian universities. Third- and fourthyear undergraduate students (i.e., those in their clinical clerkships) and medical residents, compared to other graduate students and faculty, used their mobile devices more often, used them for a broader range of activities, and purchased more resources for their devices. Conclusions: Technological and intellectual barriers do not seem to prevent medical trainees and faculty from regularly using mobile devices for their medical information searches; however, barriers to access and lack of awareness might keep them from using reliable, library-licensed resources. Implications: Libraries should focus on providing access to a smaller number of highly used mobile resources instead of a huge collection until librarylicensed mobile resources have streamlined authentication processes.
Ferrari R.,University of Alberta
Clinical Rheumatology | Year: 2015
The objectives of this paper are to to measure levels of perceived injustice in whiplash victims and determine the relationship to recovery at 6-month post-injury. Consecutive acute whiplash patients completed the Injustice Experience Questionnaire, at presentation, and also 3- and 6-month post-injury. At each of these two follow-up points, participants were examined for recovery. Of an initial 134 participants, 130 participants were followed up at 3 months and 124 at 6 months. At the 3-month follow-up, 62 % (80/130) of participants reported recovery from their injuries. At 6 months, 80 % (99/124) reported recovery. The initial Injustice Experience Questionnaire score was low, with a mean score of 6.0 ± 1.0 (range 5–10) out of a maximum of 48. The mean score at 3-month follow-up had increased in the cohort to 7.4 ± 1.6 (range 5–11). At 6-month post-injury, the mean of the Injustice Experience Questionnaire score for the cohort who still reported lack of recovery (25/124 participants) was 15.0 ± 6.0 (range 5–31), while that for the recovered group remained low at 8.2 ± 3.9 (range 5–11). In the primary care setting, a significant proportion of whiplash patients who have not recovered by 3-month post-injury subsequently develop higher levels of perceived injustice by 6-month post-injury. The development of high levels of perceived injustice at 6-month post-injury appears to follow the development of chronic pain and a lack of recovery at 3 months and, at that point, becomes a risk factor for lack of recovery thereafter. © 2014, Clinical Rheumatology.
Lerbekmo J.F.,University of Alberta
Marine and Petroleum Geology | Year: 2014
Two large asteroids struck Earth at almost the same time, 65 million years ago, causing the major extinctions recognized as ending the Mesozoic Era. Although occurring close together in time, the Earth's magnetic pole had moved from the South Pole to the North Pole in between, allowing a time difference between the impacts to be calculated. The first strike produced a ~180km diameter crater named Chicxulub on the Yucatan shelf of southern Mexico. The second hit the shelf of the northward drifting Indian continent in the southern Indian Ocean, producing a crater ~450×600km named Shiva. Hitherto, the main obstacle to verifying this scenario has been the paucity of geological sections containing evidence of both impacts. Here, we present such evidence, and conclude that the two impacts were separated by about 40,000 years. © 2013 Elsevier Ltd.
Forbes D.,University of Alberta
The Cochrane database of systematic reviews | Year: 2013
This is an update of our previous 2008 review. Several recent trials and systematic reviews of the impact of exercise on people with dementia are reporting promising findings. Primary: Do exercise programs for older people with dementia improve cognition, activities of daily living (ADLs), challenging behaviour, depression, and mortality in older people with dementia?Secondary: Do exercise programs for older people with dementia have an indirect impact on family caregivers' burden, quality of life, and mortality?Do exercise programs for older people with dementia reduce the use of healthcare services (e.g. visits to the emergency department) by participants and their family caregivers? We identified trials for inclusion in the review by searching ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group's Specialised Register, on 4 September 2011, and again on 13 August 2012. The search terms used were: 'physical activity' OR exercise OR cycling OR swim* OR gym* OR walk* OR danc* OR yoga OR 'tai chi'. In this review, we included randomized controlled trials in which older people, diagnosed with dementia, were allocated either to exercise programs or to control groups (usual care or social contact/activities) with the aim of improving cognition, ADLs, behaviour, depression, and mortality. Secondary outcomes related to the family caregiver(s) and included caregiver burden, quality of life, mortality, and use of healthcare services. Independently, at least two authors assessed the retrieved articles for inclusion, assessed methodological quality, and extracted data. Data were analysed for summary effects using RevMan 5.1 software. We calculated mean differences or standardized mean difference (SMD) for continuous data, and synthesized data for each outcome using a fixed-effect model, unless there was substantial heterogeneity between studies, when we used a random-effects model. We planned to explore heterogeneity in relation to severity and type of dementia, and type, frequency, and duration of exercise program. We also evaluated adverse events. Sixteen trials with 937 participants met the inclusion criteria. However, the required data from three trials and some of the data from a fourth trial were not published and not made available. The included trials were highly heterogeneous in terms of subtype and severity of participants' dementia, and type, duration and frequency of exercise. Only two trials included participants living at home. Our meta-analysis suggested that exercise programs might have a significant impact on improving cognitive functioning (eight trials, 329 participants; SMD 0.55, 95% confidence interval (CI) 0.02 to 1.09). However, there was substantial heterogeneity between trials (I(2) value 80%), most of which we were unable to explain. We repeated the analysis omitting one trial, an outlier, that included only participants with moderate or severe dementia. This reduced the heterogeneity somewhat (I(2) value 68%), and produced a result that was no longer significant (seven trials, 308 participants; SMD 0.31, 95% CI -0.11 to 0.74). We found a significant effect of exercise programs on the ability of people with dementia to perform ADLs (six studies, 289 participants; SMD 0.68, 95% CI 0.08 to 1.27). However, again we observed considerable unexplained statistical heterogeneity (I(2) value 77%) in this meta-analysis. This means that there is a need for caution in interpreting these findings. In further analyses, we found that the burden experienced by informal caregivers providing care in the home may be reduced when they supervise the participation of the family member with dementia in an exercise program (one study, 40 participants; MD -15.30, 95% CI -24.73 to -5.87), but we found no significant effect of exercise on challenging behaviours (one study, 110 participants; MD -0.60, 95% CI -4.22 to 3.02), or depression (six studies, 341 participants; MD -0.14, 95% CI -0.36 to 0.07) . We could not examine the remaining outcomes, quality of life, mortality, and healthcare costs, as either the appropriate data were not reported, or we did not retrieve trials that examined these outcomes. There is promising evidence that exercise programs can have a significant impact in improving ability to perform ADLs and possibly in improving cognition in people with dementia, although some caution is advised in interpreting these findings. The programs revealed no significant effect on challenging behaviours or depression. There was little or no evidence regarding the remaining outcomes of interest.
Shaw J.,University of Alberta
Journal of Quaternary Science | Year: 2010
Characteristics of large-scale fluting and hummocky terrain on the Canadian Prairies test glacial and meltwater hypotheses for landform genesis. These tests defend the meltwater model. Neither sedimentary nor glaciotectonic processes can fully explain such erosional landforms. Province-scale flow paths, which mark palaeo-ice streams and subglacial flood routes, contain large-scale fluting with flanking hummock terrain. Antecedent relief causes these paths to differ from other flood landscapes such as the Scablands. Proponents of the glacial hypothesis use an invalid analogy between Icelandic and Prairie landsystems. They suggest that groove-ploughing formed large-scale fluting, and that ice pushing created hummocky terrain. However, landform location, form, and extent, surface lags, truncated architecture, and landform associations favour the meltwater hypothesis. A simple thought experiment and clear understanding of the principle of least number of assumptions answer the criticisms that meltwater forms cannot cross-cut and that the meltwater hypothesis disregards proper hypothesis testing. An example of cross-cutting erosional marks supports this theory. No narrow tract of smoothed terrain with fluting terminates at the glacially thrust Neutral Hills, negating an important point in the glacial hypothesis. While neither the glacial hypothesis nor postglacial winnowing explain boulder and cobble lags with percussion marks, meltwater processes explain them well. © 2009 John Wiley & Sons, Ltd.
Patel A.N.,University of Alberta
Expert reviews in molecular medicine | Year: 2012
Accumulation of neurotoxic soluble amyloid-beta protein (Aβ) oligomers in the brains of patients with Alzheimer disease (AD) and their role in AD pathogenesis have emerged as topics of considerable interest in recent years. Soluble Aβ oligomers impair synaptic and neuronal function, leading to neurodegeneration that is clinically manifested by memory and cognitive dysfunction. The precise mechanisms whereby Aβ oligomers cause neurotoxicity remain unknown. Emerging insights into the mechanistic link between neuronal receptors and soluble Aβ oligomers highlight the potential role of these receptors in Aβ-mediated neurotoxicity in AD. The current review focuses on studies describing interactions between soluble Aβ oligomers and neuronal receptors, and their role in AD pathogenesis. Furthermore, these studies provide insight into potential therapies for AD using compounds directed at putative target receptors for the action of Aβ in the central nervous system. We focus on interactions of Aβ with subtypes of acetylcholine and glutamatergic receptors. Additionally, neuronal receptors such as insulin, amylin and receptor for advanced glycation end products could be potential targets for soluble Aβ-oligomer-mediated neurotoxicity. Aβ interactions with other receptors such as the p75 neurotrophin receptors, which are highly expressed on cholinergic basal forebrain neurons lost in AD, are also highlighted.
Qureshi M.J.,University of Alberta
The Cochrane database of systematic reviews | Year: 2013
The rate of retinopathy of prematurity (ROP) in moderately premature infants has decreased dramatically with improved care in the neonatal intensive care unit. A low rate of this disorder was unexpectedly observed among infants treated with intravenous D-penicillamine to prevent hyperbilirubinaemia. This observation led to the investigation of its use, both enterally as well as intravenously, to prevent ROP. To determine the effect of prophylactic administration of D-penicillamine on the incidence of acute ROP or severe ROP and other morbidities in preterm infants. We used the Cochrane Neonatal Review Group search strategy. Two review authors independently searched multiple electronic databases, previous reviews including cross references, abstracts, conference/symposia proceedings, and expert informants. We updated the search on November 27, 2012. We included randomised or quasi-randomised controlled trials if they administered D-penicillamine and compared it with no treatment or placebo to premature infants and reported on the outcome of ROP. We used the criteria and standard methods of the Cochrane Neonatal Review Group to assess the methodological quality of the included trials. One review author examined trials for validity. A second review author checked validity and they reached consensus on the final data before entry into this review. We used the standards of the Neonatal Cochrane Review Group to analyse data. Three randomised trials met the inclusion criteria. The meta-analysis showed no significant differences in the risk of any stage ROP (typical risk ratio (RR) 0.32, 95% confidence interval (CI) 0.03 to 3.70), severe ROP (typical RR 0.38, 95% CI 0.03 to 4.26) or death (typical RR 0.95, 95% CI 0.68 to 1.32) in all treated infants. When the subgroup of infants under 1500 g birth weight was examined, the results were similar. No side effects were reported, and follow-up at one year revealed no significant differences in spasticity or developmental delay. Administration of prophylactic D-penicillamine in preterm infants does not prevent acute or severe ROP, death or neurodevelopmental delay. D-penicillamine cannot be recommended for the prevention of ROP based on the available evidence.
Scrimger R.,University of Alberta
Expert Review of Anticancer Therapy | Year: 2011
Radiotherapy is an important component of the multimodality treatment of head and neck cancer. Although an effective treatment for many patients, it can have significant long-term sequelae. In particular, xerostomia - or dry mouth - caused by salivary gland injury is a serious problem suffered by most patients and leads to problems with oral comfort, dental health, speech and swallowing. This article explores the mechanisms behind radiation injury to the major salivary glands, as well as different strategies to minimize and alleviate xerostomia. This includes technical approaches to minimize radiation dose to salivary tissue, such as intensity-modulated radiotherapy and surgical transfer of salivary glands, as well as pharmacologic approaches to stimulate or protect the salivary tissue. The scientific literature will be critically examined to see what works and what strategies have been less effective in attempting to minimize xerostomia in head and neck cancer patients. © 2011 Expert Reviews Ltd.
Ferrari R.,University of Alberta
Clinical Rheumatology | Year: 2015
The objective of this study was to evaluate the Canadian Rheumatology Association Choosing Wisely recommendation concerning anti-nuclear antibody (ANA) testing. Patients with joint pain/stiffness/swelling were assessed to determine if ANA testing was indicated. An a priori threshold was set before ANA testing would be considered. Those who did not have ANA testing ordered were followed for 1 year to determine if any of them went on to have a diagnosis of systemic lupus erythematosus (SLE) or other connective tissue disease. A parallel study was conducted with a similar a priori threshold for the use of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody testing in the diagnosis of rheumatoid arthritis (RA), and again, patients were followed for 1 year. A total of 866 subjects were examined, 509 females (58.8 %) and 357 males (41.2 %). The mean age of the group was 47.5 ± 16.8 years. The mean duration of symptoms was 12.0 ± 5.6 weeks. Of the 866 subjects, 68 met an a priori threshold for ordering ANA, RF, and anti-CCP testing. Of these 68, there was a newly diagnosed case of SLE, 4 newly diagnosed cases of RA, and 3 cases of polymyalgia rheumatica. The remaining 798 subjects were followed for approximately 1 year and none developed evidence of SLE, RA, or other connective tissue disease. In the evaluation of non-specific musculoskeletal symptoms, setting an a priori threshold for ordering serology in keeping with the spirit of the Canadian Rheumatology Association Choosing Wisely recommendation for antibody testing results in a very low risk of missing a case of systemic lupus erythematosus or rheumatoid arthritis. © 2015, International League of Associations for Rheumatology (ILAR).
Phelan K.,Tulane University |
McDermid H.E.,University of Alberta
Molecular Syndromology | Year: 2011
The 22q13.3 deletion syndrome, also known as Phelan-McDermid syndrome, is a contiguous gene disorder resulting from deletion of the distal long arm of chromosome 22. In addition to normal growth and a constellation of minor dysmorphic features, this syndrome is characterized by neurological deficits which include global developmental delay, moderate to severe intellectual impairment, absent or severely delayed speech, and neonatal hypotonia. In addition, more than 50% of patients show autism or autistic-like behavior, and therefore it can be classified as a syndromic form of autism spectrum disorders (ASD). The differential diagnosis includes Angelman syndrome, velocardiofacial syndrome, fragile X syndrome, and FG syndrome. Over 600 cases of 22q13.3 deletion syndrome have been documented. Most are terminal deletions of ∼100 kb to >9 Mb, resulting from simple deletions, ring chromosomes, and unbalanced translocations. Almost all of these deletions include the gene SHANK3 which encodes a scaffold protein in the postsynaptic densities of excitatory synapses, connecting membrane-bound receptors to the actin cytoskeleton. Two mouse knockout models and cell culture experiments show that SHANK3 is involved in the structure and function of synapses and support the hypothesis that the majority of 22q13.3 deletion syndrome neurological defects are due to haploinsufficiency of SHANK3, although other genes in the region may also play a role in the syndrome. The molecular connection to ASD suggests that potential future treatments may involve modulation of metabotropic glutamate receptors. Copyright © 2011 S. Karger AG, Basel.
Jones B.,University of Alberta
Sedimentary Geology | Year: 2010
A wave-cut notch that is deeply incised into the vertical cliff faces of Cayman Brac is adorned with stalactites, stalagmites, and columns. The prefix "notch" is applied to each type of speleothem in order to distinguish them from cave speleothems. These speleothemic deposits must have formed since the highstand, ~. 125,000. years ago, which was responsible for the development of the notch. The laminated notch speleothems are formed largely of aragonite (small and large crystals) and calcite (columnar, fiber, and grain-coating mats) along with minor amounts of dolomite, a Mg-Si precipitate (kerolite?), gypsum, and halite. Laminae, typically < 2. mm thick, are commonly bounded by dissolution discontinuities that truncate the older laminae and their formative aragonite and calcite crystals. The patchy tan, grey, to green surface coloration of the notch speleothems reflects the random distribution of the subaerial biofilms, which are formed of a diverse array of filamentous and non-filamentous microbes.The notch speleothems are the integrated product of precipitation and dissolution that was, in some places, microbially mediated. Interpretations based on their mineralogy and internal structures indicate that the composition of the formative waters must have temporally fluctuated with periods of precipitation being interrupted by periods of dissolution. The microbes that formed the subaerial biofilms may have influenced some of these processes. The aragonite, calcite, and kerolite (?) probably formed as evaporation and loss of Ca through precipitation progressively increased the Mg:Ca and the Si/(Ca. +. Mg) ratios. The dolomite, gypsum, and halite probably formed during early diagenesis during the evaporation of seawater that percolated into the interiors of the notch speleothems. © 2010 Elsevier B.V.
Rosychuk R.J.,University of Alberta
Pediatric pulmonology | Year: 2010
Asthma has a high prevalence in North American children and exacerbations presenting to the emergency department (ED) setting are common. Describe the epidemiology of asthma presentations to EDs by children residing in a large geographic area (Alberta, Canada). Data were extracted from provincial administrative databases for children <18 years of age from April 1999 to March 2005. Information extracted included demographics, ED visit timing, and subsequent visits to non-ED settings. Analysis included summaries and rates. A total of 94,187 ED visits for asthma (45,385 children) were obtained. Visits were more common by boys (61.3%); after age 14, more females presented. The standardized rates remained stable over time; 21.1/1,000 in 1999/2000 compared to 19.8/1,000 in 2004/2005. Welfare recipients and Aboriginals had higher rates than other groups. Important daily, weekly, and monthly trends were seen. Approximately 10% were admitted; 5.4% of those discharged had a repeat ED visit within 7 days and 71% had not completed a non-ED follow-up visit within 7 days. The median time to the first follow-up visit was 26 days. Acute asthma is an important and relatively common ED presentation in childhood. Despite guidelines and improved treatments, this study failed to identify decreased presentation rates over time; disparities were based on age, sex, and socio-economic/cultural status. Few children were reassessed within a week of their ED visit. Further study is required to understand the factors associated with these variations and the effectiveness of interventions targeted at specific groups to reduce the asthma-related ED visits. © 2010 Wiley-Liss, Inc.
Jones B.,University of Alberta
Sedimentary Geology | Year: 2010
Nani Cave, located in dolostones of the Cayman Formation (Miocene) on Cayman Brac, contains numerous stalactites that are formed largely of aragonite and calcite along with lesser amounts of calcium-rich dolomite, gypsum, and minor amounts of Mg-Si needles. Morphologically, the dolomite is divided into blocky, filamentous mat, crust, and "beehive" types whereas the gypsum is divided into the tabular and sheet types. A diverse array of filamentous microbes and spores (probably actinomycetids) and their associated exopolysaccharides (EPS) are unevenly distributed throughout the stalactites. Although microbes are commonly present on the surfaces of the calcite and aragonite crystals, none were found inside these crystals. Similarly, no microbes were found with the gypsum. The common association of the dolomite and the Mg-Si needles with the microbes and their EPS suggests that the microbes played a formative role in the precipitation of the dolomite and Mg-Si needles. The intimate association of microbes and dolomite in these stalactites has significant implications for the origin of dolomite under low-temperature and low-pressure conditions. © 2010 Elsevier B.V.
Swaters G.E.,University of Alberta
Journal of Physical Oceanography | Year: 2010
Ekman boundary layers can lead to the destabilization of baroclinic flow in the Phillips model that, in the absence of dissipation, is nonlinearly stable in the sense of Liapunov. It is shown that the Ekman-induced instability of inviscidly stable baroclinic flow in the Phillips model occurs if and only if the kinematic phase velocity associated with the dissipation lies outside the interval bounded by the greatest and least neutrally stable Rossby wave phase velocities. Thus, Ekman-induced destabilization does not correspond to a coalescence of the barotropic and baroclinic Rossby modes as in classical inviscid baroclinic instability. The differing modal mechanisms between the two instability processes is the reason why subcritical baroclinic shears in the classical theory can be destabilized by an Ekman layer, even in the zero dissipation limit of the theory. © 2010 American Meteorological Society.
Dumberry M.,University of Alberta
Earth and Planetary Science Letters | Year: 2010
A heterogeneous heat flux at the core-mantle boundary can maintain time-averaged convective structures in the fluid core. This includes a steady pattern of heterogeneous heat flux at the inner core boundary which leads to aspherical inner core growth. If this growth pattern is longitudinally misaligned with the mantle-induced geoid, the latter would impart a gravitational torque on the newly created topography of the inner core. Allowing for continuous melting/solidification and viscous deformation of the inner core, a steady gravitationally driven differential rotation of the inner core with respect to the mantle can be sustained. In this work, we present calculations of inner core rotation driven by such a mechanism using recently published models of the heat flux at the inner core boundary and of the geoid at the base of the mantle. We show that, for a fast mean inner core growth rate of 1. mm/yr and a bulk viscous relaxation time longer than 100. yr, the inner core differential rotation can be as high as 100. deg/Myr, in the westward direction. Although this is much too slow (and in the wrong direction) to explain the seismically inferred inner core rotation (eastward, of the order of 0.2. deg/yr), this mechanism by itself would rotate the inner core by one full rotation in only a few million years. This gravitational torque would then partly offset the viscomagnetic torque from the steady eastward zonal flow near the inner core boundary, the driving mechanism typically invoked to explain a steady inner core super-rotation. Under the combined action of these two torques, the overall steady differential rotation of the inner core may then be small. This would allow the development of an inner core texture with a distinct longitudinal pattern connected to its aspherical freezing rate, as has been suggested to explain seismic observations. © 2010 Elsevier B.V.
Buriak J.M.,University of Alberta |
Buriak J.M.,Canadian National Institute For Nanotechnology
Chemistry of Materials | Year: 2014
Silicon is the cornerstone material of the semiconductor industry. As feature sizes on chips continue to decrease in size, the ratio of surface to bulk increases, and as a result, the role of surface defects, surface states and other subtle features play larger roles in the functioning of the device. Although silicon oxides have served the industry well as the passivation chemistry of choice, there is interest in expanding the repertoire of accessible and efficient chemical functional strategies available for use, and to fully understand the nature of these interfaces. For new applications such as molecular electronics on silicon and biochips, for example, there is a need to avoid the layer of intervening insulating oxide: A well-defined linkage of organic molecules through a silicon-carbon bond has great promise and appeal. Hydrosilylation, the insertion of an alkene or alkyne into a surface Si-H bond, is an ideal approach to producing these covalent Si-C bonds, and can be carried out in a number of ways. Light-promoted hydrosilylation is promising because it is clean and direct and can be patterned via masking; it requires no additional reagents such as catalysts or input of thermal energy and thus may have reduced surface contamination and numbers of defects. In this perspective, we start by making connections between the molecular silane literature, and the first reports of UV-mediated hydrosilylation of an alkene on a silicon surface, a reaction that was assumed to operate via a radical mechanism. We then describe the unexpected development of four new mechanisms that have no obvious parallels with the molecular silane literature, and take place as a result of the solid state electronics of the underlying silicon itself. From exciton involvement, to the influence of plasmonics, to the role of photoemission, the area of silicon surface hydrosilylation has become incredibly rich, and undoubtedly still contains new reactivity to be discovered. © 2013 American Chemical Society.
Richards J.P.,University of Alberta
Ore Geology Reviews | Year: 2015
This paper reviews the tectonic, magmatic, and metallogenic history of the Tethyan orogen from the Carpathians to Indochina. Focus is placed on the formation of porphyry Cu ± Mo ± Au deposits, as being the most characteristic mineral deposit type formed during both subduction and collisional processes in this region. Relatively little is known about the history of the Paleotethys ocean, which opened and closed between Gondwana and Eurasia in the Paleozoic, and few ore deposits are preserved from this period. The Neotethyan ocean opened in the Permian-Early Triassic as the Cimmerian continental fragments (the cores of Turkey, Iran, Tibet, and Indochina) rifted from the northern Gondwana margin and drifted northwards. These microcontinents docked with the Eurasian margin at various points in the Mesozoic and Cenozoic, and formed a complex archipelago involving several small back-arc basins and remnants of the Paleotethyan ocean. The main Neotethyan ocean and these smaller basins were largely eliminated by collision with India and Africa-Arabia in the early Eocene and early-mid Miocene, respectively, although Neotethyan subduction continues beneath the Hellenic arc and the Makran. The majority of porphyry-type deposits are found in association with Neotethyan subduction (mainly in the Mesozoic and Paleogene), and syn- to post-collisional events in the mid-Paleogene to Neogene. They are found throughout the orogen, but some sections are particularly well-endowed, including the Carpathians-Balkans-Rhodopes, eastern Turkey-Lesser Caucasus-NW Iran, SE Iran-SW Pakistan, southern Tibet, and SE Tibet-Indochina. Other sections that appear barren may reflect deeper levels of erosion, young sedimentary cover, or lack of exploration, although there may also be real reasons for low prospectivity in some areas, such as minimal subduction (e.g., the western Mediterranean region) or lithospheric underthrusting (as proposed in western Tibet).Over the last decade, improved geochronological constraints on the timing of ore formation and key tectonic events have revealed that many porphyry deposits that were previously assumed to be subduction-related are in fact broadly collision-related, some forming in back-arc settings in advance of collision, some during collision, and others during post-collisional processes such as orogenic collapse and/or delamination of subcontinental mantle lithosphere. While the formation of subduction-related porphyries is quite well understood, collisional metallogeny is more complex, and may involve a number of different processes or sources. These include melting of: orogenically thickened crust; previously subduction-modified lithosphere (including metasomatized mantle, underplated mafic rocks, or lower crustal arc plutons and cumulates); or upwelling asthenosphere (e.g., in response to delamination, slab breakoff, back-arc extension, or orogenic collapse). The most fertile sources for syn- and post-collisional porphyry deposits appear to be subduction-modified lithosphere, because these hydrated lithologies melt at relatively low temperatures during later tectonomagmatic events, and retain the oxidized and relatively metalliferous character of the original arc magmatism. Unusually metallically enriched lithospheric sources do not seem to be required, but the amount of residual sulfide phases in these rocks may control metal ratios (e.g., Cu:Au) in subsequent magmatic hydrothermal ore deposits. Relatively Au-rich deposits potentially form in these settings, as observed in the Carpathians (e.g., Roşia Montană), Turkey (Kisladag, Çöpler), and Iran (Sari Gunay, Dalli), although the majority of syn- and post-collisional porphyries are Cu-Mo-rich, and resemble normal subduction-related deposits (e.g., in the Gangdese belt of southern Tibet). This similarity extends to the associated igneous rocks, which, being derived from subduction-modified sources, largely retain the geochemical and isotopic character of those original arc magmas. While still retaining a broadly calc-alkaline character, these rocks may extend to mildly alkaline (shoshonitic) compositions, and may display adakite-like trace element signatures (high Sr/Y and La/Yb ratios) reflecting melting of deep crustal garnet amphibolitic sources. But they are otherwise hard to distinguish from normal subduction-related magmas.Small, post-collisional mafic, alkaline volcanic centers are common throughout the orogen, but for the most part appear to be barren. However, similar rocks in other post-subduction settings around the world are associated with important alkalic-type porphyry and epithermal Au ± Cu deposits, and the potential for discovery of such deposits in the Tethyan orogen should not be overlooked. © 2014 Elsevier B.V.
Caine V.,University of Alberta
Qualitative Health Research | Year: 2010
Drawing on the life stories of Debra, an Aboriginal woman living with HIV, I reflect on the feeling of (dis)placement from a geographic landscape and cultural heritage that both Debra and I experienced, although in different ways. I explore how place is inscribed onto and into our bodies and how home can be understood as embodied. In this way I explore place as geographic position of home and as ontological. In the living out of her stories, Debra made me not only understand the deeper conditions of human life, but that stories told are not fixed texts, that they are composed in and out of the living and in relation to others. The textual representation and physical inscriptions of Debra's stories are another way to not only understand, but to inquire into her life and my own. The inquiry deepened my understanding of nursing practice as a particular, contextual, and meaningful relational engagement. © The Author(s) 2010.
Martin C.D.,University of Alberta
Journal of Rock Mechanics and Geotechnical Engineering | Year: 2014
The initiation and propagation of failure in intact rock are a matter of fundamental importance in rock engineering. At low confining pressures, tensile fracturing initiates in samples at 40%-60% of the uniaxial compressive strength and as loading continues, and these tensile fractures increase in density, ultimately coalescing and leading to strain localization and macro-scale shear failure of the samples. The Griffith theory of brittle failure provides a simplified model and a useful basis for discussion of this process. The Hoek-Brown failure criterion provides an acceptable estimate of the peak strength for shear failure but a cutoff has been added for tensile conditions. However, neither of these criteria adequately explains the progressive coalition of tensile cracks and the final shearing of the specimens at higher confining stresses. Grain-based numerical models, in which the grain size distributions as well as the physical properties of the component grains of the rock are incorporated, have proved to be very useful in studying these more complex fracture processes. © 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences.
Dumberry M.,University of Alberta
Geophysical Journal International | Year: 2010
The temporal variation in the density structure associated with convective motions in the outer core causes a change in the Earth's gravity field. Core flows also lead to a gravity change through the global elastic deformations that accompany changes in the non-hydrostatic pressure at the core-mantle boundary (CMB). In this work, we present predictions of the gravity changes from these two processes during the past century. These predictions are built on the basis of flows at the surface of the core that are reconstructed from the observed geomagnetic secular variation. The pressure-induced gravity variations can be reconstructed directly from surface core flows under the assumption of tangential geostrophy; predicted variations in the Stokes coefficients of degree 2, 3 and 4 are of the order of 10-11, 3 × 10-12 and 10-12, respectively, with a typical timescale of a few decades. These correspond to changes in gravity of 70, 30 and 15 nGal, and to equivalent geoid height variations of 0.15, 0.05 and 0.02 mm, respectively. The density-induced gravity variations cannot be determined solely from surface core flows, though a partial recovery is possible if flows with important axial gradients dominate the dynamics at decadal timescales. If this is the case, the density-induced gravity signal is of similar amplitude and generally anti-correlated with the pressure-induced signal, thus reducing the overall amplitude of the gravity changes. However, because we expect decadal flows to be predominantly axially invariant, the amplitude of the density-induced gravity changes should be much smaller. Our prediction also allows to determine upper bounds in pressure change at the CMB and density change within the core that have taken place during the past 20 yr such that observed gravity variations are not exceeded; for harmonic degree 2, we find a maximum pressure change of approximately 350 Pa and a maximum departure from hydrostatic density of approximately 1 part in 107. Although the predicted gravity changes from core flows are small, they are at the threshold of detectability with high-precision gravity measurements from satellite missions such as GRACE. The most important challenge to identifying a core signal will be the removal of interannual gravity variations caused by surface processes which are an order of magnitude larger and mask the core signal. © 2009 The Author Journal compilation © 2009 RAS.
Unsworth M.,University of Alberta
Surveys in Geophysics | Year: 2010
Continent-continent collisions are an important tectonic process and have played a fundamental role in the evolution of the modern continents. A combination of geological and geophysical data has provided new constraints on the structure and temporal evolution of these orogens. Magnetotelluric (MT) studies have been an important part of these studies since they can constrain the fluid content and thermal structure which are key parameters for defining the rheology of the crust and upper mantle. MT studies of the Himalaya have defined the geometry of active faults associated with continued plateau growth. Orogen scale MT studies have shown that both the India-Asia collision (Tibetan Plateau and Himalaya) and the Arabia-Eurasia collision (Eastern Anatolia) have developed a low resistivity mid-crustal layer with upper surface at 10-20 km that is likely due to a combination of partial melt and associated aqueous fluids. The properties of this layer are consistent with a strength contrast that permits crustal flow over geological timescales. The upper mantle from the Moho to at least 100 km beneath both Northern Tibet and the Anatolian Plateau is characterized by low resistivity values (10-30 Ωm) indicating the presence of shallow asthenosphere. Future integrated seismic and MT studies of collision zones are needed fully to explore the 3D structures associated with deformation and further constrain geodynamic models. © Springer Science+Business Media B.V. 2009.
Maxwell E.E.,University of Alberta
Journal of Vertebrate Paleontology | Year: 2010
An ichthyosaur from the OxfordianKimmeridgian of Melville Island, Northwest Territories, Canada, is redescribed. This specimen was previously referred to as Ophthalmosaurus chrisorum Russell, 1993, but exhibits several features incompatible with this generic assignment. Here, I refer this specimen to a new genus, Arthropterygius, characterized by a basioccipital with an extremely reduced extracondylar area, a foramen for the internal carotid artery located on the posterior surface of the basisphenoid, a humerus with a well-developed distal facet for the articulation of a preaxial accessory element, and a radius and ulna with highly angular proximal surfaces for articulation with the humerus. Arthropterygius can be referred to the Ophthalmosauria based on the presence of a preaxial element anterior to the radius and ulna. This referral is supported by a phylogenetic analysis, in which a sister-group relationship between Arthropterygius and the South American genus Caypullisaurus is recovered. This specimen represents the most complete ichthyosaur from the Canadian Arctic, and has important implications for marine reptile diversity at high latitudes during the Jurassic. © 2010 by the Society of Vertebrate Paleontology.
Potts J.R.,Center for Mathematical Biology |
Lewis M.A.,Center for Mathematical Biology |
Lewis M.A.,University of Alberta
Proceedings of the Royal Society B: Biological Sciences | Year: 2014
Territory formation is ubiquitous throughout the animal kingdom. At the individual level, various behaviours attempt to exclude conspecifics fromregions of space. At the population level, animals often segregate into distinct territorial areas. Consequently, it should be possible to derive territorial patterns from the underlying behavioural processes of animal movements and interactions. Such derivations are an important element in the development of an ecological theory that can predict the effects of changing conditions on territorial populations. Here, we review the approaches developed over the past 20 years or so, which go under the umbrella of 'mechanistic territorial models'. We detail the two main strands to this research: partial differential equations and individual-based approaches, showing what each has offered to our understanding of territoriality and how they can be unified. We explain how they are related to other approaches to studying territories and home ranges, and point towards possible future directions. © 2014 The Authors.
Richards J.P.,University of Alberta
Lithos | Year: 2015
Global data for measured Fe2O3/FeO ratios and Cu contents in unaltered volcanic and intrusive arc rocks indicate that, on average, they are slightly more oxidized than other magmas derived from depleted upper mantle (such as MORB), but contain similar Cu contents across their compositional ranges. Although Cu scatters to elevated values in some intermediate composition samples, the bulk of the data show a steady but gentle trend to lower concentrations with differentiation, reaching modal values of ~50-100ppm in andesitic rocks. These data suggest that Cu is mildly compatible during partial melting and fractionation processes, likely reflecting minor degrees of sulfide saturation throughout the magmatic cycle. However, the volume of sulfides must be small such that significant proportions of the metal content remain in the magma during fractionation to intermediate compositions. Previous studies have shown that andesitic magmas containing ~50ppm Cu can readily form large porphyry-type Cu deposits upon emplacement in the upper crust.A review of the literature suggests that the elevated oxidation state in the asthenospheric mantle wedge source of arc magmas (δFMQ≈+1±1) derives from the subduction of seawater-altered and oxidized oceanic crust, and is transmitted into the mantle wedge via prograde metamorphic dehydration fluids carrying sulfate and other oxidizing components. Progressive hydration and oxidation of the mantle wedge may take up to ~10m.y. to reach a steady state from the onset of subduction, explaining the rarity of porphyry deposits in primitive island arcs, and the late formation of porphyries in continental arc magmatic cycles. Magmas generated from this metasomatized and moderately oxidized mantle source will be hydrous basalts containing high concentrations of sulfur, mainly dissolved as sulfate or sulfite. Some condensed sulfides (melt or minerals) may be present due to the high overall fS2, despite the moderately high oxidation state. These sulfides may retain some highly siderophile elements in the source, but are unlikely to be sufficiently voluminous to significantly affect the budget of more modestly sulfide-compatible and more abundant elements such as Cu and Mo. These primary magmas can therefore be considered to be largely Cu-Mo-undepleted, although highly siderophile elements such as Au and platinum group elements (PGE) may be depleted unless no sulfides remain in the source. The latter condition seems unlikely during active subduction because of the continuous flux of fresh sulfur from the slab, but may occur during post-subduction re-melting (leading to potentially Au-rich post-subduction porphyry and alkalic-type epithermal systems).Lower crustal differentiation of main-stage arc magmas results in some loss of Cu to residual or cumulate sulfides, but again the amount appears to be minor, and does not drastically reduce the Cu content of derivative intermediate-composition melts. Fractionation and devolatilization affect the oxidation state of the magma in competing ways, but, while crystallization and segregation of Fe3+-rich magnetite can cause reduction in reduced to moderately oxidized evolved magmas, this effect appears to be outweighed by the oxidative effects of degassing reduced or weakly oxidized gaseous species such as H2, H2S, and SIVO2, and preferential solvation and removal of Fe2+ in saline hydrothermal fluids. Consequently, most arc magmatic suites show slight increases in oxidation state during differentiation, reaching typical values of δFMQ=+1 to +2.This oxidation state is significant, because it corresponds to the transition from dissolved sulfide to sulfate dominance in magmas. It has been shown that Cu and Au solubilities in silicate magma increase up to this level (δFMQ. ≈. +. 1), but while Cu solubility continues to increase at higher oxidation states, Au shows a precipitous drop as sulfide, which solvates Au in the melt, is converted to sulfate. This may explain the somewhat restricted distribution of Au-rich porphyry Cu deposits, but the general association of porphyry Cu deposits with relatively oxidized magmas.Exsolution of a saline, high temperature aqueous fluid enables metals to partition from the magma into a highly mobile volatile phase. Sulfur also partitions strongly into this fluid phase, predominantly as SO2 at δFMQ=+1 to +2. However, as the fluid cools below ~400°C, SIVO2 disproportionates to form reduced H2S-II and oxidized H2SVIO4. The H2S bonds with metals in solution to precipitate as Cu- and Mo-sulfides, while the H2SO4 (and HCl) generates progressively acidic wallrock alteration (phyllic, argillic, advanced argillic). Gold may precipitate with early Cu/Mo-sulfides, but some may also stay in solution as bisulfide complexes, eventually reaching the epithermal environment.Thus, three components, [S], [H2O], and fO2 work together throughout subduction and arc magmatic processes to transport chalcophile and siderophile metals from the mantle into the upper crust, where they may be concentrated by hydrothermal processes to form ore deposits. These processes are far from 100% efficient, and metals (especially highly siderophile elements such as Au and PGE) may be left behind at various stages of the passage of arc magmas through the lithosphere, where they may form potentially metalliferous source rocks for partial melts and subsequent magmatic-hydrothermal ore deposits generated during later tectonomagmatic events. © 2014 Elsevier B.V.
Idikio H.A.,University of Alberta
International Journal of Clinical and Experimental Pathology | Year: 2010
Immunohistochemical (IHC) staining of formalin-fixed and paraffin-embedded tissues (FFPE) is widely used in diagnostic surgical pathology. All anatomical and surgical pathologists use IHC to confirm cancer cell type and possible origin of metastatic cancer of unknown primary site. What kinds of improvements in IHC are needed to boost and strengthen the use of IHC in future diagnostic pathology practice? The aim of this perspective is to suggest that continuing reliance on immunohistochemistry in cancer diagnosis, search and validation of biomarkers for predictive and prognostic studies and utility in cancer treatment selection means that minimum IHC data sets including "normalization methods" for IHC scoring, use of relative protein expression levels, use of protein functional pathways and modifications and protein cell type specificity may be needed when markers are proposed for use in diagnostic pathology. Furthermore evidence based methods (EBM), minimum criteria for diagnostic accuracy (STARD), will help in selecting antibodies for use in diagnostic pathology. In the near future, quantitative methods of proteomics, quantitative real-time polymerase chain reaction (qRT-PCR) and the use of high-throughput genomics for diagnosis and predictive decisions may become preferred tools in medicine.
McNeely M.L.,University of Alberta
Cochrane database of systematic reviews (Online) | Year: 2010
BACKGROUND: Upper-limb dysfunction is a commonly reported side effect of treatment for breast cancer and may include decreased shoulder range of motion (the range through which a joint can be moved) (ROM) and strength, pain and lymphedema. OBJECTIVES: To review randomized controlled trials (RCTs) evaluating the effectiveness of exercise interventions in preventing, minimi sing, or improving upper-limb dysfunction due to breast cancer treatment. SEARCH STRATEGY: We searched the Specialised Register of the Cochrane Breast Cancer Group, MEDLINE, EMBASE, CINAHL, and LILACS (to August 2008); contacted experts, handsearched reference lists, conference proceedings, clinical practice guidelines and other unpublished literature sources. SELECTION CRITERIA: RCTs evaluating the effectiveness and safety of exercise for upper-limb dysfunction. DATA COLLECTION AND ANALYSIS: Two authors independently performed the data abstraction. Investigators were contacted for missing data. MAIN RESULTS: We included 24 studies involving 2132 participants. Ten of the 24 were considered of adequate methodological quality.Ten studies examined the effect of early versus delayed implementation of post-operative exercise. Implementing early exercise was more effective than delayed exercise in the short term recovery of shoulder flexion ROM (Weighted Mean Difference (WMD): 10.6 degrees; 95% Confidence Interval (CI): 4.51 to 16.6); however, early exercise also resulted in a statistically significant increase in wound drainage volume (Standardized Mean Difference (SMD) 0.31; 95% CI: 0.13 to 0.49) and duration (WMD: 1.15 days; 95% CI: 0.65 to 1.65).Fourteen studies examined the effect of structured exercise compared to usual care/comparison. Of these, six were post-operative, three during adjuvant treatment and five following cancer treatment. Structured exercise programs in the post-operative period significantly improved shoulder flexion ROM in the short-term (WMD: 12.92 degrees; 95% CI: 0.69 to 25.16). Physical therapy treatment yielded additional benefit for shoulder function post-intervention (SMD: 0.77; 95% CI: 0.33 to 1.21) and at six-month follow-up (SMD: 0.75; 95% CI: 0.32 to 1.19). There was no evidence of increased risk of lymphedema from exercise at any time point. AUTHORS' CONCLUSIONS: Exercise can result in a significant and clinically meaningful improvement in shoulder ROM in women with breast cancer. In the post-operative period, consideration should be given to early implementation of exercises, although this approach may need to be carefully weighed against the potential for increases in wound drainage volume and duration. High quality research studies that closely monitor exercise prescription factors (e.g. intensity), and address persistent upper-limb dysfunction are needed.
Del Maestro A.,Johns Hopkins University |
Boninsegni M.,University of Alberta |
Affleck I.,University of British Columbia
Physical Review Letters | Year: 2011
We study the low-temperature properties of a He4 fluid confined in nanopores, using large-scale quantum Monte Carlo simulations with realistic He-He and He-pore interactions. In the narrow-pore limit, the system can be described by the quantum hydrodynamic theory known as Luttinger liquid theory with a large Luttinger parameter, corresponding to the dominance of solid tendencies and strong susceptibility to pinning by a periodic or random potential from the pore walls. On the other hand, for wider pores, the central region appears to behave like a Luttinger liquid with a smaller Luttinger parameter, and may be protected from pinning by the wall potential, offering the possibility of experimental detection of a Luttinger liquid. © 2011 American Physical Society.
Duggleby W.,University of Alberta
Journal of Palliative Care | Year: 2010
Introduction: High-quality palliative care may remain out of reach for rural people who are dying. The purpose of this study was to explore the opportunities and issues affecting the provision of high-quality palliative care from the perspective of nurses employed in two rural health regions. Method: Using an interpretive descriptive design, focus groups and in-depth individual interviews of 44 nurses were conducted. Results: Descriptions of challenges and opportunities fell into three themes: effectiveness and safety, patient-centredness, and efficiency and timeliness. Patient-centredness was seen as a major strength of rural palliative care. Major challenges included provision of adequate symptom management and support of home deaths. The scarcity of health human resources and the negative impact these shortages had on all dimensions of palliative care quality consistently underpinned the discussions. Conclusion: Implementing outcome measurements related to symptom management and home deaths may be a critical foundation for enhancing the quality of rural palliative care.
Caulfield T.,University of Alberta
Human Genetics | Year: 2011
Direct-to-consumer genetic testing continues to receive significant attention from both the popular press and policymakers. While the demand for these services has not, to date, been significant, it nevertheless seems likely that more and more individuals will be accessing DTC services. As a result, commentators have suggested that the DTC industry requires more oversight. A common rationale for policy action is that DTC services might cause undue anxiety. However, emerging evidence suggests that this is not the case. Indeed, it appears that genetic risk information has little impact on individual behavior or anxiety levels. Though more research is clearly needed, this type of research should inform the regulatory response to DTC services. © 2011 Springer-Verlag.
Sharma S.,University of Alberta
Journal of Human Nutrition and Dietetics | Year: 2010
Inuit in Nunavut (NU) and Inuvialuit in the Northwest Territories (NWT), Canada, were traditionally nomadic peoples whose culture and lifestyle were founded on hunting and gathering foods from the local environment, primarily land and marine mammals. Lifestyle changes within the last century have brought about a rapid nutrition transition, characterised by decreasing consumption of traditional foods and an associated increase in the consumption of processed, shop-bought foods. This transition may be attributed to a multitude of factors, such as acculturation, overall food access and availability, food insecurity and climate change. Obesity and risk for chronic disease are higher in the Canadian Arctic population compared with the Canadian national average. This present review describes the study population and methodologies used to collect data in order to study the nutrition transition amongst Aboriginal Arctic populations and develop Healthy Foods North (HFN), a novel, multi-institutional and culturally appropriate programme that aims to improve dietary adequacy and reduce risk of chronic disease. Included in this special issue of the Journal of Human Nutrition and Dietetics are papers describing dietary intake patterns, physical activity levels, dietary behaviours, chronic disease prevalence and psychosocial factors that potentially mediate behaviour. A further paper describes how these data were utilised to inform and develop Healthy Foods North. © 2010 The Authors. Journal compilation © 2010 The British Dietetic Association Ltd.
Ganzle M.G.,University of Alberta
Food Microbiology | Year: 2014
Enzymatic and microbial conversion of flour components during bread making determines bread quality. Metabolism of sourdough microbiota and the activity of cereal enzymes are interdependent. Acidification, oxygen consumption, and thiols accumulation by microbial metabolism modulate the activity of cereal enzymes. In turn, cereal enzymes provide substrates for bacterial growth. This review highlights the role of cereal enzymes and the metabolism of lactic acid bacteria in conversion of carbohydrates, proteins, phenolic compounds and lipids.Heterofermentative lactic acid bacteria prevailing in wheat and rye sourdoughs preferentially metabolise sucrose and maltose; the latter is released by cereal enzymes during fermentation. Sucrose supports formation of acetate by heterofermentative lactobacilli, and the formation of exopolysaccharides. The release of maltose and glucose by cereal enzymes during fermentation determines the exopolysaccharide yield in sourdough fermentations.Proteolysis is dependent on cereal proteases. Peptidase activities of sourdough lactic acid bacteria determine the accumulation of (bioactive) peptides, amino acids, and amino acid metabolites in dough and bread.Enzymatic conversion and microbial metabolism of phenolic compounds is relevant in sorghum and millet containing high levels of phenolic compounds. The presence of phenolic compounds with antimicrobial activity in sorghum selects for fermentation microbiota that are resistant to the phenolic compounds. © 2013 Elsevier Ltd.
Schindler D.W.,University of Alberta
Proceedings of the Royal Society B: Biological Sciences | Year: 2012
The management of eutrophication has been impeded by reliance on short-term experimental additions of nutrients to bottles and mesocosms. These measures of proximate nutrient limitation fail to account for the gradual changes in biogeochemical nutrient cycles and nutrient fluxes from sediments, and succession of communities that are important components of whole-ecosystem responses. Erroneous assumptions about ecosystem processes and lack of accounting for hysteresis during lake recovery have further confused management of eutrophication. I conclude that long-term, whole-ecosystem experiments and case histories of lake recovery provide the only reliable evidence for policies to reduce eutrophication. The only method that has had proven success in reducing the eutrophication of lakes is reducing input of phosphorus. There are no case histories or long-term ecosystem-scale experiments to support recent claims that to reduce eutrophication of lakes, nitrogen must be controlled instead of or in addition to phosphorus. Before expensive policies to reduce nitrogen input are implemented, they require ecosystem-scale verification. The recent claim that the 'phosphorus paradigm' for recovering lakes from eutrophication has been 'eroded' has no basis. Instead, the case for phosphorus control has been strengthened by numerous case histories and large-scale experiments spanning several decades. © 2012 The Royal Society.
Tierney K.B.,University of Alberta
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2011
Altered neurological function will generally be behaviourally apparent. Many of the behavioural models pioneered in mammalian models are portable to zebrafish. Tests are available to capture alterations in basic motor function, changes associated with exteroceptive and interoceptive sensory cues, and alterations in learning and memory performance. Excepting some endpoints involving learning, behavioural tests can be carried out at 4. days post fertilization. Given larvae can be reared quickly and in large numbers, and that software solutions are readily available from multiple vendors to automatically test behavioural responses in 96 larvae simultaneously, zebrafish are a potent and rapid model for screening neurological impairments. Coupling current and emerging behavioural endpoints with molecular techniques will permit and accelerate the determination of the mechanisms behind neurotoxicity and degeneration, as well as provide numerous means to test remedial drugs and other therapies. The emphasis of this review is to highlight unexplored/underutilized behavioural assays for future studies. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases. © 2010 Elsevier B.V.
Simmen T.,University of Alberta
Expert Opinion on Therapeutic Targets | Year: 2011
Introduction: Hax-1, the hematopoietic cell-specific protein-associated protein X-1, is an inhibitor of apoptosis, which has been implicated in severe congenital neutropenia (SCN), neurological disorders and cancer. Hax-1 over-expression, as found in numerous types of cancer, results in resistance to granzyme B and caspase-3 and stabilizes the X-linked inhibitor of apoptosis, whereas its absence or knockdown promotes apoptosis. Hax-1 is bound to the cytosolic faces of mitochondria and the endoplasmic reticulum (ER). Interestingly, numerous viral proteins, including the classical swine fever virus N-terminal protease (Npro) and human immunodeficiency virus Vpr, interact with Hax-1 and disrupt its normal localization pattern. Recent findings have demonstrated that the localization to the ER allows Hax-1 to modulate calcium signaling via interactions with polycystin-2 and sarco(endo)plasmic reticulum calcium transport ATPase 2 (SERCA2). Areas covered: This review discusses how the interaction of Hax-1 with calcium-handling proteins could dominate over its other roles in apoptosis, since Hax-1 no longer blocks apoptosis on over-expression of SERCA2. Expert opinion: To facilitate pharmacological interference with the apoptosis-regulating functions of this protein, a better understanding of the Hax-1 intracellular targeting and protein-protein interactions is needed. Such an improved understanding would allow the generation of small molecule inhibitors that interfere with apoptosis-modulating functions of Hax-1 as seen in SCN. © 2011 Informa UK, Ltd.
Davison S.N.,University of Alberta
Clinical Journal of the American Society of Nephrology | Year: 2010
Background and objectives: Despite high mortality rates, surprisingly little research has been done to study chronic kidney disease (CKD) patients' preferences for end-of-life care. The objective of this study was to evaluate end-of-life care preferences of CKD patients to help identify gaps between current end-of-life care practice and patients' preferences and to help prioritize and guide future innovation in end-of-life care policy. Design, setting, participants, & measurements: A total of 584 stage 4 and stage 5 CKD patients were surveyed as they presented to dialysis, transplantation, or predialysis clinics in a Canadian, university-based renal program between January and April 2008. Results: Participants reported relying on the nephrology staff for extensive end-of- life care needs not currently systematically integrated into their renal care, such as pain and symptom management, advance care planning, and psychosocial and spiritual support. Participants also had poor self-reported knowledge of palliative care options and of their illness trajectory. A total of 61% of patients regretted their decision to start dialysis. More patients wanted to die at home (36.1%) or in an inpatient hospice (28.8%) compared with in a hospital (27.4%). Less than 10% of patients reported having had a discussion about end-of-life care issues with their nephrologist in the past 12 months. Conclusions: Current end-of-life clinical practices do not meet the needs of patients with advanced CKD. Copyright © 2010 by the American Society of Nephrology.
He F.,Sun Yat Sen University |
He F.,University of Alberta
Ecology | Year: 2012
Underpinning the International Union for Conservation of Nature (IUCN) Red List is the assessment of extinction risk as determined by the size and degree of loss of populations. The IUCN system lists a species as Critically Endangered, Endangered, or Vulnerable if its population size declines 80%, 50%, or 30% within a given time frame. However, effective implementation of the system faces substantial challenges and uncertainty because geographic scale data on population size and long-term dynamics are scarce. I develop a model to quantify extinction risk using a measure based on a species' distribution, a much more readily obtained quantity. The model calculates the loss of the area of occupancy that is equivalent to the loss of a given proportion of a population. It is a very simple yet general model that has no free parameters and is independent of scale. The model predicted well the distributions of 302 tree species at a local scale and the distributions of 348 species of North American land birds. This area-based model provides a solution to the long-standing problem for IUCN assessments of lack of data on population sizes, and thus it will contribute to facilitating the quantification of extinction risk worldwide. © 2012 by the Ecological Society of America.
AlBalawi Z.H.,University of Alberta
The Cochrane database of systematic reviews | Year: 2013
The common cold is one of the most common illnesses in humans and constitutes an economic burden both in terms of productivity and expenditure for treatment. There is no proven cure for the common cold and symptomatic relief is the mainstay of treatment. The use of intranasal ipratropium bromide (IB) has been addressed in several studies and might prove an effective treatment for the common cold. To determine the effect of IB versus placebo or no treatment on severity of rhinorrhoea and nasal congestion in children and adults with the common cold. Subjective overall improvement was another primary outcome and side effects (for example, dry mucous membranes, epistaxis and systemic anticholinergic effects) were reported as a secondary outcome. In this updated review we searched CENTRAL 2013, Issue 3, MEDLINE (1950 to March week 4, 2013), MEDLINE in-process and other non-indexed citations (8 April 2013), EMBASE (1974 to April 2013), AMED (1985 to April 2013), Biosis (1974 to February 2011) and LILACS (1985 to April 2013). Randomised controlled trials (RCTs) comparing IB to placebo or no treatment in children and adults with the common cold. Two review authors independently extracted data and assessed trial quality. We used a standardised form to extract relevant data and we contacted trial authors for additional information. Seven trials with a total of 2144 participants were included. Four studies (1959 participants) addressed subjective change in severity of rhinorrhoea. All studies were consistent in reporting statistically significant changes in favour of IB. Nasal congestion was reported in four studies and was found to have no significant change between the two groups. Two studies found a positive response in the IB group for the global assessment of overall improvement. Side effects were more frequent in the IB group, odds ratio (OR) 2.09 (95% confidence interval (CI) 1.40 to 3.11). Commonly encountered side effects included nasal dryness, blood tinged mucus and epistaxis. The overall risk of bias in the included studies was moderate. For people with the common cold, the existing evidence, which has some limitations, suggests that IB is likely to be effective in ameliorating rhinorrhoea. IB had no effect on nasal congestion and its use was associated with more side effects compared to placebo or no treatment although these appeared to be well tolerated and self limiting. There is a need for larger, high-quality trials to determine the effectiveness of IB in relieving common cold symptoms.
Houghton M.,University of Alberta
Immunological Reviews | Year: 2011
Summary: Encouraging efficacy data have been obtained in the hepatitis C virus (HCV) chimpanzee model using prophylactic vaccines comprising adjuvanted recombinant envelope gpE1/gpE2 glycoproteins or prime/boost immunization regimens using defective adenoviruses and plasmid DNA expressing non-structural genes. While usually not resulting in sterilizing immunity after experimental challenge, the progression to chronic, persistent infection (which is responsible for HCV-associated pathogenicity in human) is inhibited. These and other vaccine candidates are in clinical development for both prophylactic as well as possible therapeutic applications. Given that other vaccines tested in the chimpanzee model may be possibly increasing the rate of chronicity, it is very important that this model continues to be available and used prior to initiation of clinical development. Several vaccine monotherapy trials in chronically infected HCV patients are resulting in small declines in viral load, suggesting that in future, combining vaccination with antiviral drug treatment may be beneficial. © 2010 John Wiley & Sons A/S.
Kell R.T.,University of Alberta
Journal of Strength and Conditioning Research | Year: 2011
The purpose of this study was to contrast the response of previously resistance-trained male and female recreational athletes with a traditionally periodized resistance training program. Sixty subjects (age = 22.8 ± 4.5 years) were assigned to 3 groups: male training (MT), n = 20; female training (FT), n = 20; and control, n = 20 (men, n = 10; women, n = 10). The MT and FT groups completed 12 weeks of traditional periodized strength training, with strength testing at baseline and at weeks 8 and 12. The training programs were identical (e.g., rest time, exercises, volume, and intensity) in both groups. In weeks 1 and 2, the FT and MT groups were trained 3 d·wk-1 (324 repetitions [reps]·wk-1) and thereafter 4 d·wk-1 (mean 642 reps·wk-1). The mean volume and intensity over the 12 weeks was 571 reps·wk-1 and 69.7% of 1 repetition maximum. Results indicated that the men were significantly (p ≤ 0. 05) stronger in absolute terms at baseline and at weeks 8 and 12. The FT group (increase = 26.2% at week 8 and 38.1% at week 12) made significantly (p ≤ 0.05) greater percent increases in strength than the MT group (increase = 17.7% at week 8 and 28.0% at week 12). The FT and MT groups made significant (p ≤ 0.05) changes in relative strength at all time points, but the MT group demonstrated greater relative strength on lateral pull-down and dumbbell shoulder press. In practical terms, the men were absolutely stronger than the women, but the women were more responsive to the periodized resistance training program. Twelve weeks of traditionally periodized resistance training induced meaningful strength gains in women (≥ 30%) and men (≥ 25%) with prior (approximately 11 months) nonperiodized resistance training experience. © 2011 National Strength and Conditioning Association.
Prochazka A.,University of Alberta
Comprehensive Physiology | Year: 2012
Animal movement is immensely varied, from the simplest reflexive responses to the most complex, dexterous voluntary tasks. Here, we focus on the control of movement in mammals, including humans. First, the sensory inputs most closely implicated in controlling movement are reviewed, with a focus on somatosensory receptors. The response properties of the large muscle receptors are examined in detail. The role of sensory input in the control of movement is then discussed, with an emphasis on the control of locomotion. The interaction between central pattern generators and sensory input, in particular in relation to stretch reflexes, timing, and pattern forming neuronal networks is examined. It is proposed that neural signals related to bodily velocity form the basic descending command that controls locomotion through specific and well-characterized relationships between muscle activation, step cycle phase durations, and biomechanical outcomes. Sensory input is crucial in modulating both the timing and pattern forming parts of this mechanism. © 2012 American Physiological Society
Prins D.,University of Alberta
Cold Spring Harbor perspectives in biology | Year: 2011
Ca(2+) is an important intracellular messenger affecting many diverse processes. In eukaryotic cells, Ca(2+) storage is achieved within specific intracellular organelles, especially the endoplasmic/sarcoplasmic reticulum, in which Ca(2+) is buffered by specific proteins known as Ca(2+) buffers. Ca(2+) buffers are a diverse group of proteins, varying in their affinities and capacities for Ca(2+), but they typically also carry out other functions within the cell. The wide range of organelles containing Ca(2+) and the evidence supporting cross-talk between these organelles suggest the existence of a dynamic network of organellar Ca(2+) signaling, mediated by a variety of organellar Ca(2+) buffers.
Prado C.M.M.,University of Alberta |
Heymsfield S.B.,Pennington Biomedical Research Center
Journal of Parenteral and Enteral Nutrition | Year: 2014
Body composition refers to the amount of fat and lean tissues in our body; it is a science that looks beyond a unit of body weight, accounting for the proportion of different tissues and its relationship to health. Although body weight and body mass index are well-known indexes of health status, most researchers agree that they are rather inaccurate measures, especially for elderly individuals and those patients with specific clinical conditions. The emerging use of imaging techniques such as dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and ultrasound imaging in the clinical setting have highlighted the importance of lean soft tissue (LST) as an independent predictor of morbidity and mortality. It is clear from emerging studies that body composition health will be vital in treatment decisions, prognostic outcomes, and quality of life in several nonclinical and clinical states. This review explores the methodologies and the emerging value of imaging techniques in the assessment of body composition, focusing on the value of LST to predict nutrition status. © 2014 American Society for Parenteral and Enteral Nutrition.
Genuis S.J.,University of Alberta
Science of the Total Environment | Year: 2010
The prevalence of allergic-related diseases, food intolerance, and chemical sensitivities in both the pediatric and adult population has increased dramatically over the last two decades, with escalating rates of associated morbidity. Conditions of acquired allergy, food intolerance and chemical hypersensitivity are frequently the direct sequelae of a toxicant induced loss of tolerance (TILT) in response to a significant initiating toxic exposure. Following the primary toxicant insult, the individuals become sensitive to low levels of diverse and unrelated triggers in their environment such as commonly encountered chemical, inhalant or food antigens. Among sensitized individuals, exposure to assorted inciting stimuli may precipitate diverse clinical and/or immune sequelae as may be evidenced by clinical symptoms as well as varied lymphocyte, antibody, or cytokine responses in some cases. Recently recognized as a mechanism of disease development, TILT and resultant sensitivity-related illness (SRI) may involve various organ systems and evoke wide-ranging physical or neuropsychological manifestations. With escalating rates of toxicant exposure and bioaccumulation in the population-at-large, an increasing proportion of contemporary illness is the direct result of TILT and ensuing SRI. Avoidance of triggers will preclude symptoms, and desensitization immunotherapy or immune suppression may ameliorate symptomatology in some cases. Resolution of SRI generally occurs on a gradual basis following the elimination of bioaccumulated toxicity and avoidance of further initiating adverse environmental exposures. As has usually been the case throughout medical history whenever new evidence regarding disease mechanisms emerges, resistance to the translation of knowledge abounds. © 2010 Elsevier B.V.
Westbury C.,University of Alberta
Journal of Psycholinguistic Research | Year: 2013
For almost 30 years, subjective familiarity has been used in psycholinguistics as an explanatory variable, allegedly able to explain many phenomena that have no other obvious explanation (Gernsbacher in J Exp Psychol General 113:256–281, 1984). In this paper, the hypothesis tested is that the subjective familiarity of words is reflecting personal familiarity with or importance of the referents of words. Using an empirically-grounded model of affective force derived from Wundt (Grundriss der Psychologie [Outlines of Psychology]. Engelmann, Leibzig, 1896) and based in a co-occurrence model of semantics (which involves no human judgment), it is shown that affective force can account for the same variance in a large set of human subjective familiarity judgments as other human subjective familiarity judgments, can predict whether people will rate new words of the same objective frequency as more or less familiar, can predict lexical access as well as human subjective familiarity judgments do, and has a predicted relationship to age of acquisition norms. Individuals who have highly affective reactivity [as measured by Carver and White’s (J Pers Soc Psychol 67(2):319–333, 1994) Behavioral Inhibition Scale and Behavioral Activation Scales] rate words as significantly more familiar than individuals who have low affective reactivity. © 2013, Springer Science+Business Media New York.
Villard M.-A.,University of Moncton |
Hache S.,University of Alberta
Biological Conservation | Year: 2012
Many authors have concluded that habitat loss has a greater influence on biodiversity than habitat fragmentation . per se. Yet, several animal species have been shown to be reluctant to move across inhospitable landscape matrices, a phenomenon that would be expected to exacerbate fragmentation effects. In this study, we tested the ability of a forest songbird (Ovenbird, . Seiurus aurocapilla) to move across two contrasting landscapes whose matrix (intensively managed forest) would be expected to be relatively permeable compared to agricultural or urban matrices. We hypothesized that males would be less likely to return to their territory in a landscape dominated by forest generally unsuitable for breeding (spruce plantations) than in another dominated by potential breeding habitat (deciduous forest). The probability of resighting translocated males (. n=. 48) on their territory was significantly lower in the plantation landscape and this relationship was consistent over two successive years. Neither translocation time nor body mass, time of capture, or structural size were significant predictors of probability of resighting. Although this species is sufficiently vagile to return quickly to its territory (e.g. one male returning in less than 2. h), these results indicate that even a forested matrix may impose a resistance to the movements of a forest bird species when its structure or composition differs from that of breeding habitat. Matrix resistance to movements potentially restricts the ability of individuals to detect and colonize suitable habitat fragments. Less vagile species would be even more affected and, therefore, we submit that a more inclusive perspective on effects of landscape change is warranted. © 2012 Elsevier Ltd.
Evans J.P.,University of North Carolina at Chapel Hill |
Meslin E.M.,Indiana University |
Marteau T.M.,Kings College London |
Caulfield T.,University of Alberta
Science | Year: 2011
Unrealistic expectations and uncritical translation of genetic discoveries may undermine other promising approaches to preventing disease and improving health.
Redescription of UALVP 40, an unusual specimen of chasmosaurus lambe, 1914 (Ceratopsidae: Chasmosaurinae) bearing long postorbital horns, and its implications for ontogeny and alpha taxonomy of the genus
Konishi T.,University of Alberta
Canadian Journal of Earth Sciences | Year: 2015
UALVP 40, an articulated and reasonably complete skull of a small chasmosaurine dinosaur collected in 1920 by George F. Sternberg from the lower unit of the Dinosaur Park Formation, Dinosaur Provincial Park, Alberta, Canada, is here redescribed. The focus of the study is on the newly prepared right side of the skull and the hitherto undescribed mandible. There are substantial differences between the right and the left side of the skull, most notably the right postorbital horncore exhibits a greater angle of inclination at 60° from horizontal, which is approximately 15° greater than that of the left. The right side of the skull also shows many unfused cranial sutures that are obliterated on the left side. These unfused sutures and the short predentary lacking an anterior elongation, indicate that UALVP 40 likely represents a subadult individual. UALVP 40 is diagnosed to the genus Chasmosaurus by its possession of the following: (i) premaxillary flange along entire anterior margin of external naris; (ii) supraorbital horns curving posteriorly along their length; and (iii) squamosal dorsal border laterally adjacent to supratemporal fenestra straight in profile, sloping posteroventrally at a shallow angle before ascending farther posteriorly to form lateral border of parietal fenestra. The last character is newly proposed. A bivariate correlation in UALVP 40 and other Canadian specimens of Chasmosaurus bearing long postorbital horncores (>150mmlong) reveals a near isometric relationship between interorbital width and horn length. This may indicate those specimens represent an ontogenetic series of a single species diagnosed by long postorbital horncores. © 2015, National Research Council of Canada. All Rights Reserved.
McFarlane S.,University of Alberta
Journal of visualized experiments : JoVE | Year: 2013
This paper discusses fluorescent core microcavity-based sensors that can operate in a microfluidic analysis setup. These structures are based on the formation of a fluorescent quantum-dot (QD) coating on the channel surface of a conventional microcapillary. Silicon QDs are especially attractive for this application, owing in part to their negligible toxicity compared to the II-VI and II-VI compound QDs, which are legislatively controlled substances in many countries. While the ensemble emission spectrum is broad and featureless, an Si-QD film on the channel wall of a capillary features a set of sharp, narrow peaks in the fluorescence spectrum, corresponding to the electromagnetic resonances for light trapped within the film. The peak wavelength of these resonances is sensitive to the external medium, thus permitting the device to function as a refractometric sensor in which the QDs never come into physical contact with the analyte. The experimental methods associated with the fabrication of the fluorescent-core microcapillaries are discussed in detail, as well as the analysis methods. Finally, a comparison is made between these structures and the more widely investigated liquid-core optical ring resonators, in terms of microfluidic sensing capabilities.
Condamine F.L.,Montpellier SupAgro |
Sperling F.A.H.,University of Alberta |
Wahlberg N.,University of Turku |
Rasplus J.-Y.,Montpellier SupAgro |
Kergoat G.J.,Montpellier SupAgro
Ecology Letters | Year: 2012
The latitudinal diversity gradient (LDG) is one of the most striking ecological patterns on our planet. Determining the evolutionary causes of this pattern remains a challenging task. To address this issue, previous LDG studies have usually relied on correlations between environmental variables and species richness, only considering evolutionary processes indirectly. Instead, we use a phylogenetically integrated approach to investigate the ecological and evolutionary processes responsible for the global LDG observed in swallowtail butterflies (Papilionidae). We find evidence for the 'diversification rate hypothesis' with different diversification rates between two similarly aged tropical and temperate clades. We conclude that the LDG is caused by (1) climatically driven changes in both clades based on evidence of responses to cooling and warming events, and (2) distinct biogeographical histories constrained by tropical niche conservatism and niche evolution. This multidisciplinary approach provides new findings that allow better understanding of the factors that shape LDGs. © 2012 Blackwell Publishing Ltd/CNRS.
Macdonald P.E.,University of Alberta
American Journal of Physiology - Endocrinology and Metabolism | Year: 2011
Whole body energy balance is ensured by the exquisite control of insulin secretion, the dysregulation of which has serious consequences. Although a great deal has been learned about the control of insulin secretion from pancreatic β-cells in the past 30 years, there remains much to be understood about the molecular mechanisms and interactions that underlie the precise control of this process. Numerous molecular interactions at the plasma membrane mediate the excitatory and amplifying events involved in insulin secretion; this includes interactions between ion channels, signal transduction machinery, and exocytotic proteins. The present Perspectives article considers evidence that key membrane and membrane-associated proteins essential to insulin secretion are regulated in concert as a functional unit, ensuring an integrated excitatory and exocytotic response to the signals that control insulin secretion. © 2011 the American Physiological Society.
Anderson C.C.,University of Alberta
Cellular and Molecular Life Sciences | Year: 2012
Melvin Cohn provides a list of experiments to test predictions of his associative antigen recognition (AAR) and Tritope models in relation to standard models of immunity. The manuscript highlights important questions and some decisive experiments testing the competing models. A central aspect of good science is the ability to pinpoint the important questions, something Cohn has, and continues here, to do with great clarity. The problems posed are presented succinctly, although knowledge of Cohn's previous theoretical contributions are needed in some areas to fully understand the path he is taking here. The importance of theory, as championed by Cohn, is a message that needs repeating, as it seems increasingly that immunologists favor description over theory. I briefly comment on each of Cohn's ten experiments and then discuss in detail a critical experiment that is missing from his list-an experiment testing the timing of antigen encounter in ontogeny as a central principle of the self non-self discrimination. © 2011 Springer Basel AG.
Sharma S.,University of Alberta
Proceedings of the Nutrition Society | Year: 2011
In nutritional epidemiology, development of valid dietary assessment instruments specific to populations in diverse settings is of paramount importance. Such instruments are essential when trying to characterise dietary patterns and intake, investigate diet-disease associations, inform and evaluate nutrition interventions, assess nutrient-gene interactions, conduct cross-country comparison studies and monitor nutrition transitions. The FFQ is a relatively inexpensive tool for measuring long-term dietary intake for large populations and for allowing researchers to track dietary changes over time. However, FFQ must be population specific to capture the local diet and available foods. Collecting 24-h dietary recalls and utilising community feedback to build the FFQ ensures that a culturally appropriate instrument is developed. This article presents several examples describing FFQ development and utilisation in different settings globally. In the Canadian Arctic, FFQ were developed and utilised to inform and evaluate a community-based intervention programme, characterise the diet and track dietary changes occurring among Inuit and Inuvialuit, populations experiencing rising rates of chronic disease and likely to be extremely vulnerable to the potential effects of climate change. Another example is an FFQ developed to assess sodium intake and evaluate a sodium reduction trial in a high-risk population in Barbados. An example is provided from Brazil, where an FFQ was developed to assess associations between diet, heterocyclic aromatic amines and colorectal adenoma among Japanese Brazilians and to conduct cross-country comparisons. These and other case studies highlight the diversity in dietary intake between populations and the need for FFQ to be developed to capture this diversity. © The Author 2011.
Liu J.,University of Alberta
Chemical Engineering Science | Year: 2013
In this work, a robust moving horizon estimation scheme augmented by an auxiliary nonlinear observer is proposed for nonlinear systems with bounded model uncertainties. Specifically, an auxiliary deterministic nonlinear observer that asymptotically tracks nominal system state is taken advantage of to calculate a confidence region that contains the actual system state taking into account the effects of bounded model uncertainties at every sampling time. This region is then used to design a constraint on the state estimates in the proposed moving horizon estimation. The proposed design brings together deterministic and optimization-based observer design techniques. First, the proposed moving horizon estimation scheme is proved to give bounded estimation errors in the case of bounded model uncertainties. Second, the proposed approach provides another option to compromise the effects of errors in arrival cost approximations and can be used together with different arrival cost approximation techniques to further improve the state estimate. The applicability and effectiveness of the proposed approach is demonstrated through the application to two chemical process examples. © 2013 Elsevier Ltd.
Heimpel M.,University of Alberta |
Aurnou J.M.,University of California at Los Angeles
Astrophysical Journal | Year: 2012
Temporal variations of Saturn's equatorial jet and magnetic field hint at rich dynamics coupling the atmosphere and the deep interior. However, it has been assumed that rotation of the interior dynamo must be steady over tens of years of modern observations. Here we use a numerical convection model and scaling estimates to show how equatorial convective bursts can transfer angular momentum to the deeper interior. The numerical model allows angular momentum transfer between a fluid outer spherical shell and a rigid inner sphere. Convection drives a prograde equatorial jet exhibiting quasiperiodic bursts that fill the equatorial volume outside the tangent cylinder. For each burst strong changes in the equatorial surface velocity are associated with retrograde torque on the inner sphere. Our results suggest that Saturn's Great White Spot, a giant storm that was observed to fill the equatorial region in 1990, could mobilize a volume of fluid carrying roughly 15% of Saturn's moment of inertia. Conservation of angular momentum then implies that a 20% change in the equatorial jet angular velocity could change the average interior rotation rate by about 0.1% - roughly an order of magnitude less than the apparent rotation rate changes associated with Saturn's kilometric radio (SKR) signal. However, if the SKR signal originates outside the liquid metal core in a "planetary tachocline" that separates the layer of fast zonal flow from the magnetically controlled and slowly convecting deep interior, then convective bursts can provide a possible mechanism for the observed 1% SKR changes. © 2012. The American Astronomical Society. All rights reserved.
Scarpella E.,University of Alberta
Cold Spring Harbor perspectives in biology | Year: 2010
Leaves are the main photosynthetic organs of vascular plants and show considerable diversity in their geometries, ranging from simple spoon-like forms to complex shapes with individual leaflets, as in compound leaves. Leaf vascular tissues, which act as conduits of both nutrients and signaling information, are organized in networks of different architectures that usually mirror the surrounding leaf shape. Understanding the processes that endow leaves and vein networks with ordered and closely aligned shapes has captured the attention of biologists and mathematicians since antiquity. Recent work has suggested that the growth regulator auxin has a key role in both initiation and elaboration of final morphology of both leaves and vascular networks. A key feature of auxin action is the existence of feedback loops through which auxin regulates its own transport. These feedbacks may facilitate the iterative generation of basic modules that underlies morphogenesis of both leaves and vasculature.
Jugdutt B.I.,University of Alberta
Heart Failure Clinics | Year: 2012
Myocardial infarction (MI) accounts for most incidences of heart failure (HF) and low ejection fraction. Evidence suggests that acute MI leads to early cardiac remodeling, with changes in ventricular geometry and structure that in turn lead to a vicious cycle of ventricular dilation, increased wall stress, hypertrophy and more ventricular dilation and dysfunction, and worsening of HF. The early geometric and structural changes contribute to early mechanical complications and subsequent progressive ventricular remodeling and the development of chronic HF. A clear understanding of the underlying mechanisms is helpful in developing optimal preventive and therapeutic strategies for HF. © 2012 Elsevier Inc.
Vance J.E.,University of Alberta
DMM Disease Models and Mechanisms | Year: 2012
Dysregulation of cholesterol homeostasis in the brain is increasingly being linked to chronic neurodegenerative disorders, including Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), Niemann-Pick type C (NPC) disease and Smith-Lemli Opitz syndrome (SLOS). However, the molecular mechanisms underlying the correlation between altered cholesterol metabolism and the neurological deficits are, for the most part, not clear. NPC disease and SLOS are caused by mutations in genes involved in the biosynthesis or intracellular trafficking of cholesterol, respectively. However, the types of neurological impairments, and the areas of the brain that are most affected, differ between these diseases. Some, but not all, studies indicate that high levels of plasma cholesterol correlate with increased risk of developing AD. Moreover, inheritance of the E4 isoform of apolipoprotein E (APOE), a cholesterol-carrying protein, markedly increases the risk of developing AD. Whether or not treatment of AD with statins is beneficial remains controversial, and any benefit of statin treatment might be due to anti-inflammatory properties of the drug. Cholesterol balance is also altered in HD and PD, although no causal link between dysregulated cholesterol homeostasis and neurodegeneration has been established. Some important considerations for treatment of neurodegenerative diseases are the impermeability of the blood-brain barrier to many therapeutic agents and difficulties in reversing brain damage that has already occurred. This article focuses on how cholesterol balance in the brain is altered in several neurodegenerative diseases, and discusses some commonalities and differences among the diseases. © 2012. Published by The Company of Biologists Ltd.
McGuire A.L.,Baylor College of Medicine |
Evans B.J.,University of Houston |
Caulfield T.,University of Alberta |
Burke W.,University of Washington
Science | Year: 2010
International cooperation and postmarket regulation are needed for Internet-based direct-to-consumer genome tests.
Nuttall M.,University of Alberta
Ambio | Year: 2012
The term "tipping point" has become increasingly popular in scientific and media usage to refer to the world in which we live, to describe the probable effects of the processes arising from the consequences of the ways we live with and transform the world, to describe our relationships with the environment, and the effects of our actions.Through this shift in scientific thinking, climate is talked about and represented as having the power to influence our lives in ways we have never before experienced or imagined, suggesting something transformative, disruptive, and decentering. Yet, in doing so, the complexity of the human world is explained in terms of scientificmodels that suggest a return to climatic determinism that simplifies our understanding of human-environment relations. How is anthropology to contribute to this discussion and to research and policy action on climate change? This article reflects on this and other questions as a way of contributing to the discussion of tipping points: are tipping points and thresholds metaphors, are they to be understood within contexts of speculative forecast, or are they descriptions of real events and indications of future change? What do we mean when we use these terms to imagine, describe, and represent the world?What relevance do they have for anticipatory knowledge and anticipatory practice? Indeed, howdoes anticipation guide us through a world of shifting conditions and sudden surprises and influence ways we orient ourselves toward the future? © 2012 Royal Swedish Academy of Sciences.
Rennie R.P.,University of Alberta
Handbook of Experimental Pharmacology | Year: 2012
Micro-organisms exist to survive. Even in the absence of antimicrobial agents, many have determinants of resistance that may be expressed phenotypically, should the need arise. With the advent of the antibiotic age, as more and more drugs were developed to treat serious infections, micro-organisms (particularly bacteria) rapidly developed resistance determinants to prevent their own demise. The most important determinants of resistance have been in the Gram-positive and Gram-negative bacteria. Among Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and penicillin-resistant Streptococcus pneumoniae (PRSP) have taxed researchers and pharmaceutical companies to develop new agents that are effective against these resistant strains. Among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBL) enzymes, carbapenemases (CREs) and the so-called amp-C enzymes that may be readily transferred between species of enterobacteriaceae and other facultative species have created multi-drug resistant organisms that are difficult to treat. Other resistance determinants have been seen in other clinically important bacterial species such as Neisseria gonorrhoeae, Clostridium difficile, Haemophilus influenzae and Mycobacterium tuberculosis. These issues have now spread to fungal agents of infection. A variety of modalities have been used to stem the tide of resistance. These include the development of niche compounds that target specific resistance determinants. Other approaches have been to find new targets for antimicrobial activity, use of combination agents that are effective against more than one target in the cell, or new delivery mechanism to maximize the concentration of antimicrobial agents at the site of infection without causing toxicity to the host. It is important that such new modalities have been proved effective for clinical therapy. Animal models and non-mammalian systems have been developed to determine if new agents will reach sufficient concentrations at infection sites to predict clinical efficacy without toxicity. It will also be key to consider antimicrobial stewardship as an important component of the continuing battle to prevent the development of antimicrobial resistance. © 2012 Springer-Verlag Berlin Heidelberg.
Wilson J.D.,University of Alberta
Quarterly Journal of the Royal Meteorological Society | Year: 2015
An approximate solution to the advection-diffusion equation is given, applying to a plume in the unstably stratified surface layer emanating from a finite ground-level area source of trace gas. The approximation consists firstly of representing the mean wind profile by a power law, and secondly, in 'splitting' the governing equation so as to determine two components of the mean concentration that, in sum, satisfy the boundary conditions. The solution, which is easy to evaluate, is compared with numerical simulations using a standard Lagrangian stochastic trajectory model (LSM) and, provided the ratio of the upwind fetch of source to the Obukhov length is not too large (|x/L|≤10), agreement is very good. The Lagrangian model, in turn, is shown to be consistent with the Project Prairie Grass (PPG) dispersion data, subject only to the tuning of a flexible constant whose optimal value carries the implication that the ratio (Sc) of the eddy viscosity to the (far field) eddy diffusivity is not unity in the neutral limit, but rather Sc≈0.64. It seems unlikely this calibration results from having neglected deposition of the PPG 'tracer' (sulphur dioxide) to the surface. © 2015 Royal Meteorological Society.
Davies E.G.R.,University of Alberta |
Simonovic S.P.,University of Western Ontario
Advances in Water Resources | Year: 2011
Awareness of increasing water scarcity has driven efforts to model global water resources for improved insight into water resources infrastructure and management strategies. Most water resources models focus explicitly on water systems and represent socio-economic and environmental change as external drivers. In contrast, the system dynamics-based integrated assessment model employed here, ANEMI, incorporates dynamic representations of these systems, so that their broader changes affect and are affected by water resources systems through feedbacks. Sectors in ANEMI therefore include the global climate system, carbon cycle, economy, population, land use and agriculture, and novel versions of the hydrological cycle, global water use and water quality. Since the model focus is on their interconnections through explicit nonlinear feedbacks, simulations with ANEMI provide insight into the nature and structure of connections between water resources and socio-economic and environmental change. Of particular interest to water resources researchers and modelers will be the simulated effects of a new water stress definition that incorporates both water quality and water quantity effects into the measurement of water scarcity. Five simulation runs demonstrate the value of wastewater treatment and reuse programs and the feedback-effects of irrigated agriculture and greater consumption of animal products. © 2011 Elsevier Ltd.
Liu X.,University of Arkansas at Little Rock |
Xu W.,University of Alberta
IEEE Transactions on Sustainable Energy | Year: 2010
In this paper, a load dispatch model is developed for the system consisting of both thermal generators and wind turbines. The probability of stochastic wind power is included in the model as a constraint. This strategy, referred to as the here-and-now approach, avoids the probabilistic infeasibility appearing in conventional models. It is shown that, based on the presented model, the impacts of stochastic wind speed on the generated power can be readily assessed. © 2010 IEEE.
Liu X.,University of Arkansas at Little Rock |
Xu W.,University of Alberta
IEEE Transactions on Power Systems | Year: 2010
In this paper we develop a load dispatch model to minimize the emission due to oxides of nitrogen (NOx). This model takes into account both thermal generators and wind turbines. We derive a closed-form in terms of the incomplete gamma function (IGF) to characterize the impact of wind power. Accordingly, the effects of wind power on emission control are investigated. The model is implemented in a computer program and a set of numerical experiments for a standard test system is reported. © 2010 IEEE.
Tsui B.C.,University of Alberta
Regional anesthesia and pain medicine | Year: 2010
This review was performed to evaluate and discuss the quality and outcomes of studies assessing ultrasound imaging in pediatric regional anesthesia. Literature searches were conducted using MEDLINE and EMBASE, combining the search term "ultrasonography" with "regional anesthesia," "nerve block," "epidural anesthesia," and "spinal anesthesia," with the limit of 0 to 18 years. Additional literature was sought from departmental files and recent issues of several major anesthesiology journals. Meta-analyses/systematic reviews, randomized controlled trials, clinical studies without either randomization or control (eg, comparative studies), and case series (n > 10) were collected, reviewed, and graded for their quality (Jadad scores) and level of evidence (Grades of Recommendation). The search resulted in 211 total publications in pediatric literature, of which 12 were included in the evaluation of peripheral nerve blocks and 12 in the evaluation of neuraxial anesthesia. Although there is some evidence to support ultrasound for various outcomes in pediatric regional anesthesia, more randomized controlled studies with sufficient power are required to further support these findings and to evaluate the potential for ultrasound to reduce complications for regional anesthesia in children.
How should we evaluate the risk of bias of physical therapy trials?: a psychometric and meta-epidemiological approach towards developing guidelines for the design, conduct, and reporting of RCTs in Physical Therapy (PT) area: a study protocol.
Armijo-Olivo S.,University of Alberta
Systematic reviews | Year: 2013
Numerous tools and items have been developed in all health areas to assess the risk of bias of randomized controlled trials (RCTs). The Cochrane Collaboration (CC) released a new tool to assess bias in RCTs, based on empirical evidence quantifying the association between some design features and estimates of treatment effects (TEs). However, this evidence is limited to medicine and investigating a selected set of components. No such studies have been conducted in other health areas such as Physical Therapy (PT) and allied health professions. Evidence specific to the PT area is needed to understand and quantify the association between design features and TE estimates to inform practice and decision-making in this field. The overall goal of this project is to provide direction for the design, conduct, reporting and bias assessment of PT RCTs. We will achieve this through the following specific objectives and methods. 1) to measure the association between methodological components and other factors (for example, PT area, type of intervention, type of outcomes) and TE estimates in RCTs in PT, 40 randomly selected meta-analyses of RCTs involving PT interventions will be identified from the Cochrane Database of Systematic Reviews. Trials will be evaluated independently by two reviewers using the most commonly used tools in the PT field. A two-level analysis will be conducted using a meta-meta-analytic approach; 2) to identify relevant items to evaluate risk of bias of PT trials, an exploratory factor analysis (EFA) will be used to identify the latent structure of the items; 3) to develop guidelines for the design, conduct, reporting, and risk of bias assessment of PT RCTs, items obtained from the factor analysis and the meta-epidemiological approach will be further evaluated by experts in PT through a web-based survey following a Delphi procedure. The results of this project will have a direct impact on research and practice in PT and are valuable to a number of stakeholders: researchers when designing, conducting, and reporting trials; systematic reviewers and meta-analysts when synthesizing trial results; physiotherapists when making day-to-day treatment decision; and, other healthcare decision-makers, such as those developing policy or practice guidelines.
Tsui B.C.H.,University of Alberta |
Suresh S.,Northwestern University
Anesthesiology | Year: 2010
Complementary to a previous publication related to pediatric extremity and trunk blockade, the authors present a comprehensive narrative review of the literature pertaining to techniques described and outcomes evaluated for ultrasound imaging in pediatric neuraxial anesthesia. The sonoanatomy related to each block is also described and illustrated to serve as a foundation for better understanding the block techniques described. For neuraxial blockade, ultrasound may fairly reliably predict the depth to loss of resistance and can enable a dynamic view of the needle and catheter after entry into the spinal canal. Particularly, in young infants, direct visualization of the needle and catheter tip may be possible, whereas in older children surrogate markers including the displacement of dura mater by the injection of fluid may be necessary for confirming needle and catheter placement. More outcome-based, prospective, randomized, controlled trials are required to prove the benefits of ultrasound when compared with conventional methods. Copyright © 2010, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.
Maksymowych W.P.,University of Alberta
Best Practice and Research: Clinical Rheumatology | Year: 2012
Radiographic assessment of spondyloarthritis constitutes the primary imaging modality for diagnostic evaluation although it is insensitive in early disease. Several years are required before definite changes can be seen in the sacroiliac joints, and magnetic resonance imaging is the preferred imaging modality when the clinical presentation suggests spondyloarthritis but the pelvic radiograph is normal or equivocal. There is little evidence that special views of the sacroiliac joints or a series of views depicting the joint are superior to a conventional antero-posterior radiograph. Studies in early disease suggest that only 30-60% of patients diagnosed with axial spondyloarthritis on clinical grounds have definite radiographic sacroiliitis. Prospective study is required for further clarity on the role of radiography in early disease. Several scoring methods have been described for the quantitative assessment of radiographic changes in the spine and hips. These methods can be used for staging of disease as well as for assessing progression in clinical trials and prognostic studies. The modified Stoke Ankylosing Spondylitis Spine Score is the preferred method for assessing progression because of its superior sensitivity to change. Nevertheless, the amount of change detected is limited, even after 2 years of follow-up, and this requires further standardisation of methodology before widespread implementation of this method. © 2012 Elsevier Ltd. All rights reserved.
Mandhane P.,University of Alberta
BMC medical research methodology | Year: 2014
BACKGROUND: Recruitment is a challenge in developing population-representative pregnancy and birth cohorts.METHODS: We developed a collaborative recruitment infrastructure (CRI) to recruit pregnant women for 4 pregnancy cohorts using: faxes from obstetrical offices, in-clinic recruiters, university and funder-driven free-media events, paid-media, and attendance at relevant tradeshows. Recruitment rates and demographic differences were compared between recruitment methods.RESULTS: We received 5008 referrals over 40 months. Compared to fax, free-media referrals were 13 times more likely to be recruited (OR 13.0, 95% CI 4.2, 40.4: p < 0.001) and paid-media referrals were 4 times more likely to be recruited (OR 4.6, 95% CI 2.1, 10.3: p < 0.001). Among paid-media advertisements, free-to-read print (e.g. Metro) was the most effective (OR 3.3, 95% CI 2.3, 4.5: p < 0.05). Several demographic differences were identified between recruitment methods and against a reference population. Between recruitment methods, media recruits had a similar proportion families with incomes ≥ $40,000 (paid-media: 94.4%; free-media: 93.3%) compared to fax recruits (95.7%), while in-clinic recruits were less likely to have family incomes ≥ $40,000 (88.8%, p < 0.05). Maternal recruits from fax and in-clinic were more likely to attend university (Fax: 92.6%, in-clinic 89.8%) versus the reference population (52.0%; p < 0.05 for both) and both were less likely to smoke (Fax: 6.8%, in-clinic 4.2%) versus reference (18.6%; p < 0.05 for both). However, while fax referrals were more likely to be Caucasian (85.9% versus reference 77.5%; p < 0.05), in-clinic referrals were not significantly different (78.2%; P > 0.05).CONCLUSION: Recruitment methods result in different recruitment rates and participant demographics. A variety of methods are required to recruit a generalizable sample.
Richards J.P.,University of Alberta
Ore Geology Reviews | Year: 2011
Metals such as Cu, Mo, Au, Sn, and W in porphyry and related epithermal mineral deposits are derived predominantly from the associated magmas, via magmatic-hydrothermal fluids exsolved upon emplacement into the mid- to upper crust. Four main sources exist for magmas, and therefore metals, in convergent and collided plate margins: the subducting oceanic plate basaltic crust, subducted seafloor sediments, the asthenospheric mantle wedge between the subducting and overriding plates, and the upper plate lithosphere. This paper firstly examines the source of normal arc magmas, and concludes that they are predominantly derived from partial melting of the metasomatized mantle wedge, with possible minor contributions from subducted sediments. Although some metals may be transferred from the subducting slab via dehydration fluids, the bulk of the metals in the resultant magmas are probably derived from the asthenospheric mantle. The most important contributions from the slab from a metallogenic perspective are H2O, S, and Cl, as well as oxidants. Partial melting of the subducted oceanic crust and/or sediments may occur under some restricted conditions, but is unlikely to be a widespread process (in Phanerozoic arcs), and does not significantly differ metallogenically from slab-dehydration processes.Primary, mantle-derived arc magmas are basaltic, but differ from mid-ocean ridge basalt in having higher water contents (~10× higher), oxidation states (~2 log fO2 units higher), and concentrations of incompatible elements and other volatiles (e.g., S and Cl). Concentrations of chalcophile and siderophile metals in these partial melts depend critically on the presence and abundance of residual sulfide phases in the mantle source. At relatively high abundances of sulfides thought to be typical of active arcs where fS2 and fO2 are high (magma/sulfide ratio=102-105), sparse, highly siderophile elements such as Au and PGE will be retained in the source, but magmas may be relatively undepleted in abundant, moderately chalcophile elements such as Cu (and perhaps Mo). Such magmas have the potential to form porphyry Cu±Mo deposits upon emplacement in the upper crust. Gold-rich porphyry deposits would only form where residual sulfide abundance was very low (magma/sulfide ratio >105), perhaps due to unusually high mantle wedge oxidation states.In contrast, some porphyry Mo and all porphyry Sn-W deposits are associated with felsic granitoids, derived primarily from melting of continental crust during intra-plate rifting events. Nevertheless, mantle-derived magmas may have a role to play as a heat source for anatexis and possibly as a source of volatiles and metals.In post-subduction tectonic settings Tulloch and Kimbrough, 2003, such as subduction reversal or migration, arc collision, continent-continent collision, and post-collisional rifting, a subducting slab source no longer exists, and magmas are predominantly derived from partial melting of the upper plate lithosphere. This lithosphere will have undergone significant modification during the previous subduction cycle, most importantly with the introduction of large volumes of hydrous, mafic (amphibolitic) cumulates residual from lower crustal differentiation of arc basalts. Small amounts of chalcophile and siderophile element-rich sulfides may also be left in these cumulates. Partial melting of these subduction-modified sources due to post-subduction thermal readjustments or asthenospheric melt invasion will generate small volumes of calc-alkaline to mildly alkaline magmas, which may redissolve residual sulfides. Such magmas have the potential to form Au-rich as well as normal Cu ± Mo porphyry and epithermal Au systems, depending on the amounts of sulfide present in the lower crustal source. Alkalic-type epithermal Au deposits are an extreme end-member of this range of post-subduction deposits, formed from subduction-modified mantle sources in extensional or transtensional environments.Ore formation in porphyry and related epithermal environments is critically dependent on the partitioning of metals from the magma into an exsolving magmatic-hydrothermal fluid phase. This process occurs most efficiently at depths greater than ~. 6. km, within large mid- to upper crustal batholithic complexes fed by arc or post-subduction magmas. Under such conditions, metals will partition efficiently into a single-phase, supercritical aqueous fluid (~. 2-13. wt.% NaCl equivalent), which may exist as a separate volatile plume or as bubbles entrained in buoyant magma. Focusing of upward flow of bubbly magma and/or fluid into the apical regions of the batholithic complex forms cupolas, which represent high mass- and heat-flux channelways towards the surface. Cupolas may be self-organizing to the extent that once formed, further magma and fluid flow will be enhanced along the weakened and heated axes. Cupolas may form initially as breccia pipes by volatile phase (rather than magma) reaming-out of extensional structures in the brittle cover rocks, to be followed immediately by magma injection to form cylindrical plugs or dikes.Cupola zones may extend to surface, where magmas and fluids vent as volcanic products and fumaroles. Between the surface and the underlying magma chamber, a very steep thermal gradient exists (700°-800°C over <5km), which is the primary cause of vertical focusing of ore mineral deposition. The bulk of metals (Cu±Mo±Au) that forms porphyry ore bodies are precipitated over a narrow temperature interval between ~425° and 320°C, where isotherms in the cupola zone rise to within ~2km of the surface. Over this temperature range, four important physical and physicochemical factors act to maximize ore mineral deposition: (1) silicate rocks transition from ductile to brittle behavior, thereby greatly enhancing fracture permeability and enabling a threefold pressure drop; (2) silica shows retrograde solubility, thereby further enhancing permeability and porosity for ore deposition; (3) Cu solubility dramatically decreases; and (4) SO2 dissolved in the magmatic-hydrothermal fluid phase disproportionates to H2S and H2SO4, leading to sulfide and sulfate mineral deposition and the onset of increasingly acidic alteration.The bulk of the metal flux into the porphyry environment may be carried by moderately saline supercritical fluids or vapors, with a volumetrically lesser amount by saline liquid condensates. However, these vapors rapidly become dilute at lower temperatures and pressures, such that they lose their capacity to transport metals as chloride complexes. They retain significant concentrations of sulfur species, however, and bisulfide complexing of Cu and Au may enable their continued transport into the epithermal regime. In the high-sulfidation epithermal environment, intense acidic (advanced-argillic) alteration is caused by the flux of highly acidic magmatic volatiles (H2SO4, HCl) in this vapor phase. Ore formation, however, is paragenetically late, and may be located in these extremely altered and leached cap rocks largely because of their high permeability and porosity, rather than there being any direct genetic connection. Ore-forming fluids, where observed, are low- to moderate-salinity liquids, and are thought to represent later-stage magmatic-hydrothermal fluids that have ascended along shallower (cooler) geothermal gradients that either do not, or barely, intersect the liquid-vapor solvus. Such fluids "contract" from the original supercritical fluid or vapor to the liquid phase. Brief intersection of the liquid-vapor solvus may be important in shedding excess chloride and chloride-complexed metals (such as Fe), so that bisulfide-complexed metals remain in solution. Such a restrictive pressure-temperature path is likely to occur only transiently during the evolution of a magmatic-hydrothermal system, which may explain the rarity of high-sulfidation Cu-Au ore deposits, despite the ubiquitous occurrence of advanced-argillic alteration in the lithocaps above porphyry-type systems. © 2011 Elsevier B.V.
Klerk A.D.,University of Alberta
Energy and Environmental Science | Year: 2011
Carbon sources, such as coal, natural gas, biomass and waste, can be converted into transportation fuels by combining appropriate gasification, Fischer-Tropsch and refining technologies. Efficient refining of the Fischer-Tropsch synthesis derived syncrude requires a different approach to refinery design than commonly applied to crude oil refinery design. The design of refineries to optimise the production of on-specification motor-gasoline, jet fuel and diesel fuel respectively from both high temperature Fischer-Tropsch (HTFT) syncrude and low temperature Fischer-Tropsch (LTFT) are considered. Refinery designs are presented for the production of motor-gasoline and jet fuel with better than 50% yield (better than 70% selectivity on transportation fuel), without resorting to very complex designs. Only diesel fuel refining presented a problem, since the production of on-specification EN590:2004 diesel fuel is limited by a Fischer-Tropsch specific cetane-density-yield trade-off. The compound classes that are required to produce diesel fuel in high yield that meet both minimum cetane number and minimum density requirements are not abundant in Fischer-Tropsch syncrude. Refinery designs for diesel fuel production was limited to a yield of less than 25% EN 590:2004 compliant diesel fuel. This yield restriction does not apply when diesel fuel specifications do not have a minimum density requirement. © 2011 The Royal Society of Chemistry.
Shirgaokar M.,University of Alberta
Journal of Transport Geography | Year: 2014
In the Greater Mumbai Region (GMR), jobs and housing are agglomerating in nodes in the periphery of Mumbai City. However, current transportation investments focus on strengthening connections within Mumbai City, while these outlying nodes have received less attention. As housing and jobs move out, given limited travel choices, the need for mobility nudges many middle class Indian households into owning private vehicles. Using household travel survey data from the GMR, this paper develops an understanding of how worker's trips are different for those who commute to the city versus the exurbs. Socio-economic and transportation indicators for middle class workers going to the city versus the exurbs show that these populations are quite similar demographically. However, those traveling to the exurbs, on average, tend to be at a socio-economic disadvantage with respect to income, education and out-of-pocket travel burdens. Those traveling to exurban work locations have shorter travel times and trip distances, and make much higher use of walking, biking, rickshaws, and motorized two-wheelers compared to commuters to Mumbai City. Across the GMR, car users travel longer and farther compared to motorized two-wheeler users. On average, traveling by a private vehicle is faster than bus or rickshaw travel revealing advantages of private vehicle use. These mode choices in the middle class have resulted in rapid motorization and negative externalities such as traffic congestion and emissions. Evidence of large increases in motorized two-wheelers and cars in India suggests that these modes will likely keep growing, unless competing efficient travel options are supplied. © 2014 Elsevier Ltd.
Butts C.A.,University of Alberta
Translational Lung Cancer Research | Year: 2013
The demonstration that systemic chemotherapy improves survival in patients who have had resection of early stage non-small cell lung cancer (NSCLC) represents a significant advance. The absolute benefit of adjuvant chemotherapy in this setting is small with an overall survival improvement of 5%. In addition, there are many patients who have contraindications to cisplatin-based adjuvant therapy. Adjuvant chemotherapy is intended to target systemic micrometastases that remain after primary resection. The observation that cancers can relapse months or years after initial surgery implies that the residual micrometastases exist in a latent or dormant state. The concept of tumor dormancy offers therapeutic potential through induction or maintenance of the dormant state in disseminated tumor cells or through eradication of these dormant cells. Cancer dormancy is a complex process with multiple potential mechanisms. This review will focus on some of the evidence for immune related tumor dormancy and the potential for immune therapies to improve outcomes in the adjuvant setting in NSCLC. © Translational lung cancer research. All rights reserved.
Palmer A.R.,University of Alberta
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution | Year: 2012
Natural selection eliminates phenotypic variation from populations, generation after generation-an observation that haunted Darwin. So, how does new phenotypic variation arise, and is it always random with respect to fitness? Repeated behavioral responses to a novel environment-particularly those that are learned-are typically advantageous. If those behaviors yield more extreme or novel morphological variants via developmental plasticity, then previously cryptic genetic variation may be exposed to natural selection. Significantly, because the mean phenotypic effect of "use and disuse" is also typically favorable, previously cryptic genetic variation can be transformed into phenotypic variation that is both visible to selection and biased in an adaptive direction. Therefore, use-induced developmental plasticity in a very real sense "creates" new phenotypic variation that is nonrandom with respect to fitness, in contrast to the random phenotypic effects of mutation, recombination, and "direct effects" of environment (stress, nutrition). I offer here (a) a brief review of the immense literature on the effects of "use and disuse" on morphology, (b) a simple yet general model illustrating how cryptic genetic variation may be exposed to selection by developmentally plastic responses that alter trait performance in response to "use and disuse," and (c) a more detailed model of a positive feedback loop between learning (handed behavior) and morphological plasticity (use-induced morphological asymmetry) that may rapidly generate novel phenotypic variation and facilitate the evolution of conspicuous morphological asymmetries. Evidence from several sources suggests that handed behaviors played an important role both in the origin of novel forms (asymmetries) and in their subsequent evolution. © 2011 Wiley Periodicals, Inc., A Wiley Company.
Courneya K.S.,University of Alberta
International Journal of Behavioral Nutrition and Physical Activity | Year: 2010
Background: The widespread incorporation of behavioral support interventions into exercise trials has sometimes caused confusion concerning the primary purpose of a trial. The purpose of the present paper is to offer some conceptual and methodological distinctions among three types of exercise trials with a view towards improving their design, conduct, reporting, and interpretation.Discussion: Exercise trials can be divided into "health outcome trials" or "behavior change trials" based on their primary outcome. Health outcome trials can be further divided into efficacy and effectiveness trials based on their potential for dissemination into practice. Exercise efficacy trials may achieve high levels of exercise adherence by supervising the exercise over a short intervention period ("traditional" exercise efficacy trials) or by the adoption of an extensive behavioral support intervention designed to accommodate unsupervised exercise and/or an extended intervention period ("contemporary" exercise efficacy trials). Exercise effectiveness trials may emanate from the desire to test exercise interventions with proven efficacy ("traditional" exercise effectiveness trials) or the desire to test behavioral support interventions with proven feasibility ("contemporary" exercise effectiveness trials). Efficacy, effectiveness, and behavior change trials often differ in terms of their primary and secondary outcomes, theoretical models adopted, selection of participants, nature of the exercise and comparison interventions, nature of the behavioral support intervention, sample size calculation, and interpretation of trial results.Summary: Exercise researchers are encouraged to clarify the primary purpose of their trial to facilitate its design, conduct, and interpretation. © 2010 Courneya; licensee BioMed Central Ltd.
Keeping D.,University of Alberta
Animal Conservation | Year: 2014
Limited resources in conservation dictate the need for efficient means of assessing wildlife abundance. Body mass-day range scaling rules and empirical track counts were applied to an established formula to estimate a wide range of wildlife densities. Using the southern Kalahari ecosystem of Botswana as an example, I provide the first comprehensive density estimates for the mammalian wildlife community (>0.2kg), including densities for several species previously unattainable by other methods. Among a subset of species, empirical day ranges from this area were consistently greater than those predicted using scaling rules modeled with species from diverse ecosystems. I applied a correction factor based on this discrepancy, which generated values congruent with independent density estimates from the area. Although accurate measures of day range are a practical constraint to estimating densities from track counts, the results suggest that modest efforts to obtain location-specific day range estimates for a subset of species can improve density estimates for others derived from general allometric relationships. Given the strength of track surveys to accumulate unbiased observations quickly, in environments where animal tracks are readily visible, this approach shows potential for the rapid assessment of wildlife abundance. © 2014 The Zoological Society of London.
Grant R.F.,University of Alberta
Ecological Modelling | Year: 2014
Effects of climate warming on ecosystem productivity are strongly influenced by those on mineralization and uptake of key soil nutrients, particularly N. Models used to project these effects must therefore include a comprehensive and fully coupled N cycle which has undergone rigorous testing. Key hypotheses governing the response of the N cycle to warming in the terrestrial ecosystem model ecosys were tested against changes in ecosystem C and N stocks measured during 7 years of 5°C soil heating in the Harvard soil heating experiment. These hypotheses enabled the model to simulate gains in plant C stocks that rose from 50 to 200gCm-2y-1 driven by increased N mineralization and uptake as the soil heating experiment progressed. However these gains were offset by continuing losses of soil C stocks from 125 to 250gCm-2y-1 driven by increased heterotrophic respiration, so that total C stocks changed little with soil heating. Both gains and losses in the model were consistent with those measured in the soil heating experiment. The changes in N cycling with soil heating on which these model results were based were further corroborated by comparing modelled vs. measured increases in soil N mineralization rates, foliar N contents and reductions in root phytomass, and by comparing modelled increases in CO2 fluxes and net primary productivity with those reported in meta-analyses of warming effects on ecosystem productivity. However when the model was run under gradual climate warming by 5°C per century, these modelled changes in N cycling drove gains in ecosystem C stocks that rose gradually to ca. 165gCm-2y-1 after 100 years. The greater gain in ecosystem C modelled under gradual climate warming vs. sudden soil heating was attributed to much smaller losses in soil C stocks. © 2014 Elsevier B.V.
Vogel J.A.,University of Alberta
Critical Care Medicine | Year: 2014
OBJECTIVE:: To evaluate whether using long-axis or short-axis view during ultrasound-guided internal jugular and subclavian central venous catheterization results in fewer skin breaks, decreased time to cannulation, and fewer posterior wall penetrations.DESIGN:: Prospective, randomized crossover study.SETTING:: Urban emergency department with approximate annual census of 60,000.SUBJECTS:: Emergency medicine resident physicians at the Denver Health Residency in Emergency Medicine, a postgraduate year 1–4 training program.INTERVENTIONS:: Resident physicians blinded to the study hypothesis used ultrasound guidance to cannulate the internal jugular and subclavian of a human torso mannequin using the long-axis and short-axis views at each site.MEASUREMENTS AND MAIN RESULTS:: An ultrasound fellow recorded skin breaks, redirections, and time to cannulation. An experienced ultrasound fellow or attending used a convex 8–4 MHz transducer during cannulation to monitor the needle path and determine posterior wall penetration. Generalized linear mixed models with a random subject effect were used to compare time to cannulation, number of skin breaks and redirections, and posterior wall penetration of the long axis and short axis at each cannulation site. Twenty-eight resident physicians participated: eight postgraduate year 1, eight postgraduate year 2, five postgraduate year 3, and seven postgraduate year 4. The median (interquartile range) number of total internal jugular central venous catheters placed was 27 (interquartile range, 9–42) and subclavian was six catheters (interquartile range, 2–20). The median number of previous ultrasound-guided internal jugular catheters was 25 (interquartile range, 9–40), and ultrasound-guided subclavian catheters were three (interquartile range, 0–5). The long-axis view was associated with a significant decrease in the number of redirections at the internal jugular and subclavian sites, relative risk 0.4 (95% CI, 0.2–0.9) and relative risk 0.5 (95% CI, 0.3–0.7), respectively. There was no significant difference in the number of skin breaks between the long axis and short axis at the subclavian and internal jugular sites. The long-axis view for subclavian was associated with decreased time to cannulation; there was no significant difference in time between the short-axis and long-axis views at the internal jugular site. The prevalence of posterior wall penetration was internal jugular short axis 25%, internal jugular long axis 21%, subclavian short axis 64%, and subclavian long axis 39%. The odds of posterior wall penetration were significantly less in the subclavian long axis (odds ratio, 0.3; 95% CI, 0.1–0.9).CONCLUSIONS:: The long-axis view for the internal jugular was more efficient than the short-axis view with fewer redirections. The long-axis view for subclavian central venous catheterization was also more efficient with decreased time to cannulation and fewer redirections. The long-axis approach to subclavian central venous catheterization is also associated with fewer posterior wall penetrations. Using the long-axis view for subclavian central venous catheterization and avoiding posterior wall penetrations may result in fewer central venous catheter–related complications. © 2014 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins
Shapiro A.M.J.,University of Alberta
Current Opinion in Organ Transplantation | Year: 2011
Purpose of review: The current review addresses a critical need in clinical islet transplantation, namely the routine transition from the requirement of two to four donors down to one donor per recipient. The ability to achieve single-donor islet transplantation will provide many more islet grafts for treatment of an ever-expanding patient base with type 1 diabetes (T1DM) with poor glycemic control. Avoiding exposure of recipients to multiple different donor human leukocyte associated (HLA) antigens is critical if risk of donor sensitization is to be avoided. This point is important as further islet or pancreas transplants in the remote future or the potential future need for a solid organ kidney transplant may become prohibitive if the recipient is sensitized. Recent findings: This review addresses systematically all areas that contribute to the success or failure of single-donor islet engraftment, beginning with donor-related factors, optimizing islet isolation and culture conditions, and describes a series of strategies in the treatment of the recipient to prevent inflammation, apoptosis, islet thrombosis, and improve metabolic functional outcome, all of which will lead to improved single-donor engraftment success. Summary: If single-donor islet transplantation can be achieved routinely, therapy will become more widely available, more accepted by the transplant community (currently pancreas transplantation requires only a single donor), and this situation will have a major impact overall as an effective treatment option in T1DM. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Shoute L.C.T.,University of Alberta
ChemPhysChem | Year: 2010
A thin-film of dielectric on a reflecting surface constituting a multilayer substrate modulates light intensity due to the interference effect. A nanostructure consisting of randomly oriented silver particles of different shapes, sizes, and interparticle spacings supports multiple plasmon resonances and is observed to have a broad extinction spectrum that spans the entire visible region. Combining the two systems by fabricating the nanostructure on the thin-dielectric film of the multilayer substrate yields a new composite structure which is observed to modulate both the extinction spectrum and the SERS EF (surface enhanced Raman scattering enhancement factor) of the nanostructure as the thickness of the thin-film dielectric is varied. The frequency and intensity of the visible extinction spectrum vary dramatically with the dielectric thickness and in the intermediate thickness range the spectrum has no visible band. The SERS EF determined for the composite structure as a function of the thin-film dielectric thickness varies by several orders of magnitude. Strong correlation between the magnitude of the SERS EF and the extinction intensity is observed over the entire dielectric thickness range indicating that the extinction spectrum corresponds to the excitation of the plasmon resonances of the nanostructure. A significant finding which has potential applications is that the composite structure has synergic effect to boost SERS EF of the nanostructure by an order of magnitude or more compared to the same nanostructure on an unlayered substrate. © 2010 Wiley-VCH Verlag GmbH& Co. KGaA, Weinheim.
Matthaei S.,Diabetes Zentrum Quakenbruck |
Bowering K.,University of Alberta |
Rohwedder K.,Astrazeneca |
Grohl A.,Aptiv Solutions |
Diabetes Care | Year: 2015
OBJECTIVE To evaluate the efficacy and safety of dapagliflozin in patients with type 2 diabetes inadequately controlled with metformin and sulfonylurea. RESEARCH DESIGN AND METHODS Patients with HbA1c of 7.0% (53 mmol/mol) to 10.5% (91 mmol/mol) receiving sulfonylurea and metformin were randomized to receive dapagliflozin 10 mg/day (n = 109) or placebo (n = 109) for 24 weeks. RESULTS HbA1c (baseline: dapagliflozin 8.08% [65mmol/mol]; placebo 8.24% [67mmol/mol]) and fasting plasma glucose (baseline: dapagliflozin 167.4 mg/dL [9.29 mmol/L]; placebo 180.5 mg/dL [10.02 mmol/L]) significantly improved from baseline with dapagliflozin (placebo-subtracted change -0.69% [-7.5 mmol/mol], P < 0.0001; -33.5 mg/dL [-1.86 mmol/L], P < 0.0001, respectively). More patients achieved a therapeutic glycemic response (HbA1c <7.0% [53 mmol/mol]) with dapagliflozin (31.8%) versus placebo (11.1%) (P < 0.0001). Body weight and systolic blood pressure were significantly reduced from baseline over 24 and 8 weeks, respectively, with dapagliflozin (placebo-subtracted change -2.1 kg, P < 0.0001; -3.8 mmHg, P = 0.0250). Patients receiving dapagliflozin showed placebo-subtracted increases in total, LDL, and HDL cholesterol (11.4 mg/dL, P = 0.0091; 11.4 mg/dL, P = 0.0030; 2.2 mg/dL, P = 0.0172, respectively) with no change in LDL/HDL cholesterol ratio (0.1; P = 0.2008) or triglycerides (-16.5 mg/dL; P = 0.1755). Adverse events occurred in 48.6% of patients receiving dapagliflozin and 51.4% receiving placebo. Significantly more patients with dapagliflozin compared with placebo experienced hypoglycemia (12.8 vs. 3.7%; P = 0.024) and genital infections (5.5 vs. 0%; P = 0.029). Events of urinary tract infection were reported by 6.4% of patients in both groups. CONCLUSIONS Dapagliflozin was well tolerated and effective over 24 weeks as add-on to metformin plus sulfonylurea. Adverse effects included hypoglycemia and genital infections. © 2015 by the American Diabetes Association.
Luyckx V.A.,University of Alberta |
Bertram J.F.,Monash University |
Brenner B.M.,Harvard University |
Fall C.,MRC Lifecourse Epidemiology Unit |
And 3 more authors.
The Lancet | Year: 2013
Summary Developmental programming of non-communicable diseases is now an established paradigm. With respect to hypertension and chronic kidney disease, adverse events experienced in utero can affect development of the fetal kidney and reduce final nephron number. Low birthweight and prematurity are the most consistent clinical surrogates for a low nephron number and are associated with increased risk of hypertension, proteinuria, and kidney disease in later life. Rapid weight gain in childhood or adolescence further compounds these risks. Low birthweight, prematurity, and rapid childhood weight gain should alert clinicians to an individual's lifelong risk of hypertension and kidney disease, prompting education to minimise additional risk factors and ensuring follow-up. Birthweight and prematurity are affected substantially by maternal nutrition and health during pregnancy. Optimisation of maternal health and early childhood nutrition could, therefore, attenuate this programming cycle and reduce the global burden of hypertension and kidney disease in the future. © 2013 Elsevier Ltd.
Zochodne D.W.,University of Alberta
Handbook of Clinical Neurology | Year: 2014
Diabetic polyneuropathy (DPN) is a common but intractable degenerative disorder of peripheral neurons. DPN first results in retraction and loss of sensory terminals in target organs such as the skin, whereas the perikarya (cell bodies) of neurons are relatively preserved. This is important because it implies that regrowth of distal terminals, rather than neuron replacement or rescue, may be useful clinically. Although a number of neuronal molecular abnormalities have been examined in experimental DPN, several are prominent: loss of structural proteins, neuropeptides, and neurotrophic receptors; upregulation of "stress" and "repair" proteins; elevated nitric oxide synthesis; increased AGE-RAGE signaling, NF-κB and PKC; altered neuron survival pathways; changes of pain-related ion channel investment. There is also a role for abnormalities of direct signaling of neurons by insulin, an important trophic factor for neurons that express its receptors. While evidence implicating each of these pathways has emerged, how they link together and result in neuronal degeneration remains unclear. However, several offer interesting new avenues for more definitive therapy of this condition. © 2014 Elsevier B.V.
Levine A.,Pediatric Gastroenterology Unit |
Wine E.,University of Alberta
Inflammatory Bowel Diseases | Year: 2013
Crohn's disease is a complex inherited disorder of unknown pathogenesis with environmental, genetic, and microbial factors involved in the development of the disease. A remarkable feature of this disease, especially, but not limited to childhood, is the effective response to exclusive enteral nutrition therapy and the observed benefit from exclusion of normal diet (principle of exclusivity). We reviewed the possible mechanisms of action of enteral nutrition for induction of remission and provided a hypothetical model (herein termed bacterial penetration cycle) that integrates dietary components, bacteria, susceptibility genes, and the innate immune response in the pathogenesis of Crohn's disease. Copyright ©; 2013 Crohn's & Colitis Foundation of America, Inc.
Deyholos M.K.,University of Alberta
Plant, Cell and Environment | Year: 2010
More than 100 different studies of plant transcriptomic responses to salinity or drought-related stress have now been published. Most of these use microarrays or related high-throughput profiling technologies. This compels us to ask three questions in review: (1) what has transcriptomics contributed to our understanding of stress physiology; (2) what limits the ability of transcriptomics to contribute to increases in stress tolerance; and (3) given these limits, what are the most appropriate uses of transcriptomics? We conclude that although microarrays are now a mature technology that accurately describes the transcriptome, the consistently low correlation between transcript abundance and other measures of gene expression imposes an inherent limitation that cannot be ignored. Further limitations on the relevance of transcriptomics arise in some cases from experimental practices related to the treatment regimen and the selection of tissue or germplasm. Nevertheless, there is good evidence to support the continued use of transcriptomics, especially emerging techniques such as RNA-Seq, as a screening tool for candidate gene discovery. Microarrays can also be valuable in analysing the transcriptome per se (e.g. when describing the phenotype of a transcription factor mutant or discovering non-coding RNA species), and when integrated with other types of data including metabolomic analyses. © 2010 Blackwell Publishing Ltd.
Guirguis L.M.,University of Alberta
Patient Education and Counseling | Year: 2011
Objective: To characterize pharmacists' experience and explore their beliefs toward an interactive communication technique, the three prime questions (3PQs),where pharmacists ask about patients' understanding of medication's purpose, directions, and monitoring. Methods: Mixed method design. Pharmacists were briefly trained and then integrated the 3PQs into their practice for two weeks. Pharmacists recorded their perceptions of patient interactions, completed a survey addressing self-efficacy and role beliefs toward the 3PQs, and participated in a focus group. Results: Eleven pharmacists participated and the 3PQs were used with 176 patients. Most interactions were under 5. min. Pharmacists reported that questions about directions and monitoring were most effective in gathering new information with refills whereas medication purpose question was preferred for new fills. The majority of pharmacists were certain they could use the 3PQs and agreed it was their role. Five themes arose from the qualitative analysis: established communication routines, enhanced patient-pharmacist relationships, good medication history, tailoring of the 3PQs, and impact of pharmacy organization. Conclusion: The 3PQs enabled pharmacists to briefly assess patient medication experiences and tailor education while fostering patient-centered relationships in pharmacy practice. Practice implications: While the 3PQs may enhance pharmacists' patient assessment; integration may challenge pharmacists' work routine. © 2011 Elsevier Ireland Ltd.
Birch D.W.,University of Alberta
Cochrane database of systematic reviews (Online) | Year: 2011
Intraoperative hypothermia during both open and laparoscopic abdominal surgery may be associated with adverse events. For laparoscopic abdominal surgery, the use of heated insufflation systems for establishing pneumoperitoneum has been described to prevent hypothermia. Humidification of the insufflated gas is also possible. Past studies have shown inconclusive results with regards to maintenance of core temperature and reduction of postoperative pain and recovery times. To determine the effect of heated gas insufflation on patient outcomes following minimally invasive abdominal surgery. The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (PubMed), EMBASE, International Pharmaceutical Abstracts (IPA), Web of Science, Scopus, www.clinicaltrials.gov and the National Research Register were searched (1956 to 14 June 2010). Grey literature and cross-references were also searched. Searches were limited to human studies without language restriction. All included studies were randomized trials comparing heated (with or without humidification) gas insufflation with cold gas insufflation in adult and pediatric populations undergoing minimally invasive abdominal procedures. Study quality was assessed in regards to relevance, design, sequence generation, allocation concealment, blinding, possibility of incomplete data and selective reporting. The selection of studies for the review was done independently by two authors, with any disagreement resolved in consensus with a third co-author. Screening of eligible studies, data extraction and methodological quality assessment of the trials were performed by the authors. Data from eligible studies were collected using data sheets. Results were presented using mean differences for continuous outcomes and relative risks with 95% confidence intervals for dichotomous outcomes. The estimated effects were calculated using the latest version of RevMan software. Publication bias was taken into consideration and funnel plots were compiled. Sixteen studies were included in the analysis. During laparoscopic abdominal surgery, no effect on postoperative pain nor changes in core temperature, morphine consumption, length of hospitalisation, lens fogging, length of operation or recovery room stay were associated with heated compared to cold gas insufflation with or without humidification. The study offers evidence that during laparoscopic abdominal surgery, heated gas insufflation, with or without humidification, has minimal benefit on patient outcomes.
Gamon J.A.,University of Alberta |
Bond B.,Oregon State University
Remote Sensing of Environment | Year: 2013
Using the "photochemical reflectance index" (PRI) as a measure of xanthophyll pigment activity and photosynthetic light-use efficiency, we examined physiological responses to diurnal illumination in mature forest stands. In a Douglas-fir forest in Corvallis, Oregon, PRI varied primarily with illumination, which was strongly influenced by canopy aspect and time of day. Once normalized for illumination, PRI exhibited a pattern of midday depression similar to that of leaf photosynthesis and stomatal conductance. Comparable optical responses to illumination were detected at canopy and leaf scales, demonstrating that remote spectroradiometry could be applied to monitor photosynthetic downregulation in uniform, closed stands. In similar measurements at a ponderosa pine forest in Black Butte, Oregon, an old tree exhibited more suppressed midday PRI values than a young tree, once values were normalized for illumination. Unlike the PRI response in Douglas-fir, variation in the diurnal PRI response between individual ponderosa pine trees was a predominant source of PRI variation. This contrasting age effect was consistent with other studies at this site showing reduced midday photosynthesis and stomatal conductance in old trees due to hydraulic limitations. These results indicate that diurnal and spatial patterns of photosynthetic activity in structurally complex evergreen forest stands can be characterized with narrow-band spectral reflectance, provided measurements are properly normalized by illumination. These findings also support recent studies using field and satellite remote sensing that report strong effects of illumination on the PRI signal from forest stands, and provide additional evidence that individual canopy responses can reveal contrasting degrees of photosynthetic downregulation due to varying stress effects within a single forest stand. Together, these results support the hypothesis that photosynthesis is coordinately regulated, allowing PRI to detect changing levels of stomatal activity and carboxylation. While illumination patterns and photosynthetic downregulation both influenced PRI, pigment pool sizes and enhanced PRI under prolonged low light provided additional sources of PRI variation in the canopy signal. Further understanding of these multiple PRI responses could help realize the goal of remote sensing of photosynthetic activity using PRI. © 2013 Elsevier Inc.
Bonifas A.P.,Ohio State University |
Bonifas A.P.,Canadian National Institute For Nanotechnology |
McCreery R.L.,Canadian National Institute For Nanotechnology |
McCreery R.L.,University of Alberta
Nature Nanotechnology | Year: 2010
Virtually all types of molecular electronic devices depend on electronically addressing a molecule or molecular layer through the formation of a metallic contact. The introduction of molecular devices into integrated circuits will probably depend on the formation of contacts using a vapour deposition technique, but this approach frequently results in the metal atoms penetrating or damaging the molecular layer. Here, we report a method of forming soft metallic contacts on molecular layers through surface-diffusion-mediated deposition, in which the metal atoms are deposited remotely and then diffuse onto the molecular layer, thus eliminating the problems of penetration and damage. Molecular junctions fabricated by this method exhibit excellent yield (typically >90%) and reproducibility, and allow examination of the effects of molecular-layer structure, thickness and contact work function. © 2010 Macmillan Publishers Limited. All rights reserved.
Omar Faruque M.O.,Florida State University |
Dinavahi V.,University of Alberta
IEEE Transactions on Industrial Electronics | Year: 2010
This paper presents the hardware-in-the-loop (HIL) simulation of power electronic systems using a unique adaptive discretization technique based on the input of the system, where the coefficient matrices and system equations are changed while the simulation is running. The voltage-source-converter (VSC)-based HVDC system is used as a case study. Two z-transform-based discretization techniques, known as the step-invariant transformation (SIT) and the ramp-invariant transformation, and one of their derivative time-shifted SIT are applied for simulating the VSC-HVDC system. Discrete switching synchronization algorithms are used to accommodate the asynchronous events that take place in between two discrete simulation points. The HIL simulation is implemented using an off-the-shelf PC cluster interfaced with a digital controller. The simulator and the controller are connected through I/O ports, which facilitate the exchange of analog and digital signals. A 4-kW VSC-HVDC experimental setup is used to validate the simulation results, using the same digital controller as that in the HIL simulation to supply the necessary gate pulses for the experimental VSCs. A comparative study of the results obtained through offline, HIL simulation, and the experiment is presented. © 2010 IEEE.
Mendez P.F.,University of Alberta
Science and Technology of Welding and Joining | Year: 2011
The present paper addresses the renewed need to focus on the physics of welding to realise the full potential of the latest welding technologies which include fibre and disc lasers, friction stir welding and inverter power supplies. The approach to understanding, synthesis and generalization in other engineering branches is reviewed, highlighting the central role of handbook type solution in the conceptual design stage. It is shown that the multiphysics and multicoupled aspects of welding exceed the capabilities of other engineering approaches and the methodology of scaling is proposed as a promising alternative. The application of scaling to friction stir welding is shown through an example in which the maximum temperature in the metal is generalised into a power law, experimental and numerical data are synthesised into a general correction factor, and secondary effects are captured as dimensionless groups. © 2011 Institute of Materials, Minerals and Mining.
Churchill C.D.M.,University of Alberta
Chemical Physics Letters | Year: 2012
The magnitudes of select π-π interactions are studied with MP2, as well as the fragment molecular orbital (FMO) method, which evaluates the total energy as a sum of polarized monomer energies and interfragment interaction energies. The monomer polarization is of particular interest and is found to increase in magnitude with system size and the electrostatic contribution to the interaction. As a result, differences will exist in the interaction energy reported from FMO calculations, and those calculated using a traditional supermolecular approach. © 2012 Elsevier B.V. All rights reserved.
Glenn N.M.,University of Alberta
Qualitative Health Research | Year: 2013
Perhaps we want to be perfect, strive for health, beauty, and the admiring gaze of others. Maybe we desire the body of our youth, the "healthy" body, the body that has just the right fit. Regardless of the motivation, we might find ourselves striving, wanting, and waiting on weight loss. What is it to wait on weight loss? I explore the meaning of this experience-as-lived using van Manen's guide to phenomenological reflection and writing. Weight has become an increasing focus of contemporary culture, demonstrated, for example, by a growing weight-loss industry and global obesity "epidemic." Weight has become synonymous with health status, and weight loss with "healthier. " I examine the weight wait through experiences of the common and uncommon, considering relations to time, body, space, and the other with the aim of evoking a felt, embodied, emotive understanding of the meaning of waiting on weight loss. I also discuss the implications of the findings. © The Author(s) 2012.
Frolov V.P.,University of Alberta
Physical Review Letters | Year: 2015
We study a spherical gravitational collapse of a small mass in higher-derivative and ghost-free theories of gravity. By boosting a solution of linearized equations for a static point mass in such theories we obtain in the Penrose limit the gravitational field of an ultrarelativistic particle. Taking a superposition of such solutions we construct a metric of a collapsing null shell in the linearized higher-derivative and ghost-free gravity. The latter allows one to find the gravitational field of a thick null shell. By analyzing these solutions we demonstrate that in a wide class of the higher dimensional theories of gravity as well as for the ghost-free gravity there exists a mass gap for mini-black-hole production. We also found conditions when the curvature invariants remain finite at r=0 for the collapse of the thick null shell. © 2015 American Physical Society.
Wagg A.,University of Alberta |
Dale M.,MAC Clinical Research |
Tretter R.,Astellas Pharma Global Development |
Stow B.,Astellas Pharma Europe |
Compion G.,Astellas Pharma Europe
European Urology | Year: 2013
Background: Compared with younger people, the elderly are more likely to suffer from overactive bladder (OAB) and to have other chronic conditions that affect physical or cognitive function. Despite this, there are few data on the cognitive safety of antimuscarinic agents in older patients and none that examine the effect of these agents on those with mild cognitive impairment (MCI). Objective: To evaluate cognitive effects during chronic stable dosing with solifenacin and oxybutynin versus placebo in older (≥75 yr) subjects with MCI. Design, setting, and participants: A randomised, double-blind, triple-crossover trial in 26 elderly volunteers with MCI. Cognitive function was assessed using Cognitive Drug Research (CDR) computerised testing. Intervention: Three treatment periods of 21 d each with solifenacin 5 mg once daily, oxybutynin 5 mg twice daily, or placebo, separated by 21-d washout periods. Outcome measurements and statistical analysis: The primary end point was change from baseline in cognitive function with solifenacin at 6 h postdose and oxybutynin at 2 h postdose (time points close to their predicted time to peak concentration). Secondary end points included change in cognitive function at additional time points, and safety and tolerability assessments. Results and limitations: Neither agent was associated with significant changes from baseline in any of the five standard, composite outcomes of cognitive function (power of attention, continuity of attention, quality of working memory, quality of episodic memory, and speed of memory). In a secondary analysis, oxybutynin was associated with significant decreases in power and continuity of attention versus placebo at 1-2 h postdose. Both agents were well tolerated, with the most frequently reported adverse event being mild or moderate dry mouth. Conclusions: Solifenacin had no detectable effect on cognition in this group of elderly people with MCI. © 2013 European Association of Urology.
Idikio H.A.,University of Alberta
PLoS ONE | Year: 2011
Background: Cancer biomarkers are sought to support cancer diagnosis, predict cancer patient response to treatment and survival. Identifying reliable biomarkers for predicting cancer treatment response needs understanding of all aspects of cancer cell death and survival. Galectin-3 and Beclin1 are involved in two coordinated pathways of programmed cell death, apoptosis and autophagy and are linked to necroptosis/necrosis. The aim of the study was to quantify galectin-3 and Beclin1 mRNA in human cancer tissue cDNA panels and determine their utility as biomarkers of cancer cell survival. Methods and Results: A panel of 96 cDNAs from eight (8) different normal and cancer tissue types were used for quantitative real-time polymerase chain reaction (qRT-PCR) using ABI7900HT. Miner2.0, a web-based 4- and 3- parameter logistic regression software was used to derive individual well polymerase chain reaction efficiencies (E) and cycle threshold (Ct) values. Miner software derived formula was used to calculate mRNA levels and then fold changes. The ratios of cancer to normal tissue levels of galectin-3 and Beclin1 were calculated (using the mean for each tissue type). Relative mRNA expressions for galectin-3 were higher than for Beclin1 in all tissue (normal and cancer) types. In cancer tissues, breast, kidney, thyroid and prostate had the highest galectin-3 mRNA levels compared to normal tissues. High levels of Beclin1 mRNA levels were in liver and prostate cancers when compared to normal tissues. Breast, kidney and thyroid cancers had high galectin-3 levels and low Beclin1 levels. Conclusion: Galectin-3 expression patterns in normal and cancer tissues support its reported roles in human cancer. Beclin1 expression pattern supports its roles in cancer cell survival and in treatment response. qRT-PCR analysis method used may enable high throughput studies to generate molecular biomarker sets for diagnosis and predicting cancer treatment response. © 2011 Halliday A. Idikio.
Wang Y.F.,ATCO Electric |
Li Y.W.,University of Alberta
IEEE Transactions on Power Electronics | Year: 2013
Single-phase grid-connected converters are widely used in many applications such as photovoltaics, fuel cells, active power filters, etc. An important topic for the development of their control schemes is ac signal detection, such as grid phase detection for grid-interfacing inverters, and harmonic detection for harmonic compensation devices. Since only one signal is available, the task is more difficult than in three-phase systems. Among the existing methods, the frequency-domain ones are known to have a one-cycle delay and heavier computational burden. Meanwhile, the time-domain methods often rely on phase-locked loop, quadrature signal generation, and complex filtering techniques; the resulted multiple-looped system may suffer from slow transients and stability issues. This paper proposes a new detection method based on anticonjugate harmonic decomposition and cascaded delayed signal cancellation. The method uses constant zero as the quadrature signal, and has a completely open-looped structure. The resulted detection system is very simple and robust. The fundamental and harmonic detection transients can be as short as 0.47 cycle in most cases, or 1.5 cycles for cases with considerable frequency variations. Meanwhile, zero steady-state error can be guaranteed in complicated harmonic scenarios, including all typical single-phase system harmonics. The performance of the proposed detection method is verified by experiments. © 1986-2012 IEEE.
Sameoto D.,University of Alberta |
Menon C.,Simon Fraser University
Smart Materials and Structures | Year: 2010
In the past two years, there have been a large number of publications on the topic of biomimetic dry adhesives from modeling, fabrication and testing perspectives. We review and compare the most recent advances in fabrication and testing of these materials. While there is increased convergence and consensus as to what makes a good dry adhesive, the fabrication of these materials is still challenging, particularly for anisotropic or hierarchal designs. Although qualitative comparisons between different adhesive designs can be made, quantifying the exact performance and rating each design is significantly hampered by the lack of standardized testing methods. Manufacturing dry adhesives, which can reliably adhere to rough surfaces, show directional and self-cleaning behavior and are relatively simple to manufacture, is still very challenging-great strides by multiple research groups have however made these goals appear achievable within the next few years. © 2010 IOP Publishing Ltd.
Pass B.,University of Alberta
ESAIM - Control, Optimisation and Calculus of Variations | Year: 2013
We study a form of optimal transportation surplus functions which arise in hedonic pricing models. We derive a formula for the Ma-Trudinger-Wang curvature of these functions, yielding necessary and sufficient conditions for them to satisfy (A3w). We use this to give explicit new examples of surplus functions satisfying (A3w), of the form b(x,y) = H(x + y) where H is a convex function on â n. We also show that the distribution of equilibrium contracts in this hedonic pricing model is absolutely continuous with respect to Lebesgue measure, implying that buyers are fully separated by the contracts they sign, a result of potential economic interest. © EDP Sciences, SMAI, 2013.
Wagg A.S.,University of Alberta
Drugs and Aging | Year: 2012
Overactive bladder is a common condition that increases in prevalence in association with age. Antimuscarinic therapy remains the mainstay of pharmacological treatment for the condition, and there is an increasing body of evidence that supports the use of these drugs. Despite this, and because of concerns about associated adverse effects, older people are less likely to receive active treatment for their condition. This review considers some of the factors that need to be taken into account when using these medications. © 2012, Springer International Publishing AG.
Warnick C.M.,University of Alberta
Communications in Mathematical Physics | Year: 2013
We consider the massive wave equation on asymptotically AdS spaces. We show that the timelike I behaves like a finite timelike boundary, on which one may impose the equivalent of Dirichlet, Neumann or Robin conditions for a range of (negative) mass parameter which includes the conformally coupled case. We demonstrate well posedness for the associated initial-boundary value problems at the H 1 level of regularity. We also prove that higher regularity may be obtained, together with an asymptotic expansion for the field near I. The proofs rely on energy methods, tailored to the modified energy introduced by Breitenlohner and Freedman. We do not assume the spacetime is stationary, nor that the wave equation separates. © 2013 Springer-Verlag Berlin Heidelberg.
Woolgar E.,University of Alberta
Classical and Quantum Gravity | Year: 2013
The Bakry-Émery generalized Ricci tensor arises in scalar-tensor gravitation theories in the conformal gauge known as the Jordan frame. Recent results from the mathematics literature show that standard singularity and splitting theorems that hold when an energy condition is applied in general relativity also hold when that energy condition is applied to the Bakry-Émery tensor. We show here that a direct consequence is that the Hawking-Penrose singularity theorem and the timelike splitting theorem hold for scalar-tensor theory in the Jordan frame. As examples, we consider dilaton gravity (including totally anti-symmetric torsion) and the Brans-Dicke family of scalar-tensor theories. For Brans-Dicke theory the theorems do not extend to cover the entire space of values of the Brans-Dicke family parameter ω, and so may fail to hold for ω < -1. Observations show that this range of values does not describe our Universe, but the result is in accord with examples in the literature of Brans-Dicke spacetimes that have no singularity in the Jordan frame and do not split as a Riemannian product. © 2013 IOP Publishing Ltd.
Han Z.,University of Alberta
Photonics and Nanostructures - Fundamentals and Applications | Year: 2010
Among various plasmonic waveguides, the metal-insulator-metal (MIM) type is the most promising for true subwavelength photonic integration. To date, many photonic devices based on MIM waveguides have been investigated, including resonators. However, most of the reported MIM ring resonators suffer from low extinction ratios and the reasons are unexplored in the literature. In this paper, we present a comprehensive analysis of the underlying causes of the low performance of MIM ring resonators, and give the analytical transmission relation for a universal all-pass ring resonator with coupling loss. Based on the analysis we propose plasmonic racetrack resonators in MIM waveguides and show that the performance can be greatly improved. © 2010 Elsevier B.V. All rights reserved.
Page D.N.,University of Alberta
Journal of Cosmology and Astroparticle Physics | Year: 2013
Recently there has been much discussion as to whether old black holes have firewalls at their surfaces that would destroy infalling observers. Though I suspect that a proper handling of nonlocality in quantum gravity may show that firewalls do not exist, it is interesting to consider an extension of the firewall idea to what seems to be the logically possible concept of hyper-entropic gravitational hot objects (gravitational fireballs or grireballs for short) that have more entropy than ordinary black holes of the same mass. Here some properties of such grireballs are discussed under various assumptions, such as assuming that their radii and entropies both go as powers of their masses as the one independent parameter, or assuming that their radii depend on both their masses and their entropies as two independent parameters. © 2013 IOP Publishing Ltd and Sissa Medialab srl.
Egerton R.F.,University of Alberta
Microscopy and Microanalysis | Year: 2013
Equations governing the elastic scattering of electrons are applied to the knock-on displacement of atoms along a substrate, yielding analytical expressions for the surface-translation energy, threshold incident energy, and displacement rate. For a surface perpendicular to the incident beam, scattering angles around 90° contribute most to the kinetic energy of surface atoms. Tilting the specimen lowers the threshold incident energy for displacement and leads to anisotropy in the atomic motion but has little effect on the directionally-averaged displacement rate. The rate of beam-induced adatom motion is predicted to exceed that of room-temperature thermal motion when the surface-diffusion energy is greater than about 0.5 eV. © Microscopy Society of America 2013.
Page D.N.,University of Alberta
Journal of Cosmology and Astroparticle Physics | Year: 2013
If a black hole starts in a pure quantum state and evaporates completely by a unitary process, the von Neumann entropy of the Hawking radiation initially increases and then decreases back to zero when the black hole has disappeared. Here numerical results are given for an approximation to the time dependence of the radiation entropy under an assumption of fast scrambling, for large nonrotating black holes that emit essentially only photons and gravitons. The maximum of the von Neumann entropy then occurs after about 53.81% of the evaporation time, when the black hole has lost about 40.25% of its original Bekenstein-Hawking (BH) entropy (an upper bound for its von Neumann entropy) and then has a BH entropy that equals the entropy in the radiation, which is about 59.75% of the original BH entropy 4πM0 2, or about 7.509M0 2 6.268 × 1076(M 0/Mȯ)2, using my 1976 calculations that the photon and graviton emission process into empty space gives about 1.4847 times the BH entropy loss of the black hole. Results are also given for black holes in initially impure states. If the black hole starts in a maximally mixed state, the von Neumann entropy of the Hawking radiation increases from zero up to a maximum of about 119.51% of the original BH entropy, or about 15.018M 0 2 1.254 × 1077(M0/M ȯ)2, and then decreases back down to 4πM 0 2 = 1.049 × 1077(M0/M ȯ)2. © 2013 IOP Publishing Ltd and Sissa Medialab srl.
Creutzig T.,University of Alberta |
Ridout D.,Australian National University
Nuclear Physics B | Year: 2013
This article gives a complete account of the modular properties and Verlinde formula for conformal field theories based on the affine Kac-Moody algebra sl̂(2) at an arbitrary admissible level k. Starting from spectral flow and the structure theory of relaxed highest weight modules, characters are computed and modular transformations are derived for every irreducible admissible module. The culmination is the application of a continuous version of the Verlinde formula to deduce non-negative integer structure coefficients which are identified with Grothendieck fusion coefficients. The Grothendieck fusion rules are determined explicitly. These rules reproduce the well-known "fusion rules" of Koh and Sorba, negative coefficients included, upon quotienting the Grothendieck fusion ring by a certain ideal. © 2013 Elsevier B.V.
Roland J.,University of Alberta |
Matter S.F.,University of Cincinnati
Ecology | Year: 2013
We examined the long-term, 15-year pattern of population change in a network of 21 Rocky Mountain populations of Parnassius smintheus butterflies in response to climatic variation. We found that winter values of the broadscale climate variable, the Pacific Decadal Oscillation (PDO) index, were a strong predictor of annual population growth, much more so than were endogenous biotic factors related to population density. The relationship between PDO and population growth was nonlinear. Populations declined in years with extreme winter PDO values, when there were either extremely warm or extremely cold sea surface temperatures in the eastern Pacific relative to that in the western Pacific. Results suggest that more variable winters, and more frequent extremely cold or warm winters, will result in more frequent decline of these populations, a pattern exacerbated by the trend for increasingly variable winters seen over the past century. © 2013 by the Ecological Society of America.
Lang V.Y.,University of Alberta
Pharmacogenetics and genomics | Year: 2012
The common ATP-sensitive potassium (KATP) channel variants E23K and S1369A, found in the KCNJ11 and ABCC8 genes, respectively, form a haplotype that is associated with an increased risk for type 2 diabetes. Our previous studies showed that KATP channel inhibition by the A-site sulfonylurea gliclazide was increased in the K23/A1369 haplotype. Therefore, we studied the pharmacogenomics of seven clinically used sulfonylureas and glinides to determine their structure-activity relationships in KATP channels containing either the E23/S1369 nonrisk or K23/A1369 risk haplotypes. The patch-clamp technique was used to determine sulfonylurea and glinide inhibition of recombinant human KATP channels containing either the E23/S1369 or the K23/A1369 haplotype. KATP channels containing the K23/A1369 risk haplotype were significantly less sensitive to inhibition by tolbutamide, chlorpropamide, and glimepiride (IC50 values for K23/A1369 vs. E23/S1369=1.15 vs. 0.71 μmol/l; 4.19 vs. 3.04 μmol/l; 4.38 vs. 2.41 nmol/l, respectively). In contrast, KATP channels containing the K23/A1369 haplotype were significantly more sensitive to inhibition by mitiglinide (IC50=9.73 vs. 28.19 nmol/l for K23/A1369 vs. E23/S1369) and gliclazide. Nateglinide, glipizide, and glibenclamide showed similar inhibitory profiles in KATP channels containing either haplotype. Our results demonstrate that the ring-fused pyrrole moiety in several A-site drugs likely underlies the observed inhibitory potency of these drugs on KATP channels containing the K23/A1369 risk haplotype. It may therefore be possible to tailor existing therapy or design novel drugs that display an increased efficacy in type 2 diabetes patients homozygous for these common KATP channel haplotypes.
Warnick C.M.,University of Alberta |
Warnick C.M.,University of Warwick
Communications in Mathematical Physics | Year: 2014
We consider the problem of quasinormal modes (QNM) for strongly hyperbolic systems on stationary, asymptotically anti-de Sitter black holes, with very general boundary conditions at infinity. We argue that for a time slicing regular at the horizon the QNM should be identified with certain Hk eigenvalues of the infinitesimal generator A of the solution semigroup. Using this definition we are able to prove directly that the quasinormal frequencies form a discrete, countable subset of C which in the globally stationary case accumulates only at infinity. We avoid any need for meromorphic extension, and the quasinormal modes are honest eigenfunctions of an operator on a Hilbert space. Our results apply to any of the linear fields usually considered (Klein- Gordon, Maxwell, Dirac, etc.) on a stationary black hole background, and do not rely on any separability or analyticity properties of the metric. Our methods and results largely extend to the locally stationary case. We provide a counter-example to the conjecture that quasinormal modes are complete. We relate our approach directly to the approach via meromorphic continuation. © 2014, Springer-Verlag Berlin Heidelberg.
Ries N.M.,University of Alberta
Healthcare Policy | Year: 2012
Rising rates of overweight and obesity are of serious concern in Canada. Until recently, discussion of policy options to promote healthier lifestyles has ignored the topic of direct financial incentives. The idea of paying people to lose weight or adopt healthier behaviours is now attracting study and debate. Some governments and companies are already experimenting with reward programs. Available evidence indicates that financial incentives help promote short-term change, but there is a dearth of evidence on longer-term programs and outcomes. Targeted incentives for specific risk groups have shown more success. With creative design, targeted use and evaluation, financial incentives for weight loss and healthy behaviour may be a useful addition to the health policy toolkit.
Forhan M.,University of Alberta |
Gill S.V.,Boston University
Best Practice and Research: Clinical Endocrinology and Metabolism | Year: 2013