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Calgary, Canada

The University of Calgary is a public research university located in Calgary, Alberta, Canada. Founded in 1966 the University of Calgary is composed of 14 faculties and more than 85 research institutes and centres.More than 25,000 undergraduate and 6,000 graduate students are currently enrolled. The University of Calgary has graduated over 155,000 alumni in 152 countries, including the current Prime Minister of Canada, Stephen Harper, and Canadian astronaut Robert Thirsk.The University of Calgary is one of Canada’s top research universities and is a member of the U15 .The University of Calgary is the birthplace of a number of important inventions, including the neurochip. The university's sponsored research revenue of $352 million, with total revenues exceeding $1.1 billion, is one of the highest in the country. Being in Calgary, with Canada's highest concentration of engineers and geoscientists, the Faculty of Science, Department of Geoscience and the Schulich School of Engineering maintain ties to the petroleum and geoscience industry.The main campus is located in the north-west quadrant of Calgary, near the Bow River, and covers more than 200 hectares or 494.2 acre. Wikipedia.

Berry D.W.,University of Waterloo | Lvovsky A.I.,University of Calgary
Physical Review Letters | Year: 2010

We answer the question whether linear-optical processing of the states produced by one or multiple imperfect single-photon sources can improve the single-photon fidelity. This processing can include arbitrary interferometers, coherent states, feedforward, and conditioning on results of detections. We show that without introducing multiphoton components, the single-photon fraction in any of the single-mode states resulting from such processing cannot be made to exceed the efficiency of the best available photon source. If multiphoton components are allowed, the single-photon fidelity cannot be increased beyond 1/2. We propose a natural general definition of the quantum-optical state efficiency, and show that it cannot increase under linear-optical processing. © 2010 The American Physical Society. Source

Postoperative atrial fibrillation and atrial flutter (POAF) are the most common complications of cardiac surgery that require intervention or prolong intensive care unit and total hospital stay. For some patients, these tachyarrhythmias have important consequences including patient discomfort/anxiety, hemodynamic deterioration, cognitive impairment, thromboembolic events including stroke, exposure to the risks of antiarrhythmic treatments, longer hospital stay, and increased health care costs. We conclude that prevention of POAF is a worthwhile exercise and recommend that the dominant therapy for this purpose be/β-blocker therapy, especially the continuation of/β-blocker therapy that is already in place. When/β-blocker therapy is contraindi-cated, amiodarone prophylaxis is recommended. If both of these therapies are contraindicated, therapy with either intravenous magnesium or biatrial pacing is suggested. Patients at high risk of POAF may be considered for first-line amiodarone therapy, first-line sotalol therapy, or combination prophylactic therapy. The treatment of POAF may follow either a rate-control approach (with the dominant therapy being β-blocking drugs) or a rhythm-control approach. Anticoagulation should be considered if persistent PO AF lasts >72 hours and at the point of hospital discharge. The ongoing need for any POAF treatment (including anticoagulation) should be reconsidered 6-12 weeks after the surgical procedure. © 2011 Canadian Cardiovascular Society. Source

β-Cell mass increases during pregnancy in adaptation to the insulin resistance of pregnancy. This increase is accompanied by an increase in β-cell proliferation, a process that requires intact prolactin receptor (Prlr) signalling. Previously, it was found that during pregnancy, heterozygous prolactin receptor-null (Prlr+/-) mice had lower number of β-cells, lower serum insulin and higher blood glucose levels than wild-type (Prlr+/+) mice. An unexpected observation was that the glucose homeostasis of the experimental mouse depends on the genotype of her mother, such that within the Prlr+/+ group, the Prlr+/+ offspring derived from Prlr+/+ mothers (Prlr+/+(+/+)) had higher β-cell mass and lower blood glucose than those derived from Prlr+/- mothers (Prlr+/+(+/-)). Pathways that are known to regulate β-cell proliferation during pregnancy include insulin receptor substrate-2, Akt, menin, the serotonin synthetic enzyme tryptophan hydroxylase-1, Forkhead box M1 and Forkhead box D3. The aim of the present study was to determine whether dysregulation in these signalling molecules in the islets could explain the maternal effect on the phenotype of the offspring. It was found that the pregnancy-induced increases in insulin receptor substrate-2 and Akt expression in the islets were attenuated in the Prlr+/+(+/-) mice in comparison to the Prlr+/+(+/+) mice. The expression of Forkhead box D3, which plays a permissive role for β-cell proliferation during pregnancy, was also lower in the Prlr+/+(+/-) mice. In contrast, the pregnancy-induced increases in phospho-Jak2, tryptophan hydroxylase-1 and FoxM1, as well as the pregnancy-associated reduction in menin expression, were comparable between the two groups. There was also no difference in expression levels of genes that regulate insulin synthesis and secretion (i.e. glucose transporter 2, glucokinase and pancreatic and duodenal homeobox-1) between these two groups. Taken together, these results suggest that the in utero environment of the Prlr+/- mother confers long-term changes in the pancreatic islets of her offspring such that when the offspring themselves became pregnant, they cannot adapt to the increased insulin demands of their own pregnancy. © 2013 The Author. The Journal of Physiology © 2013 The Physiological Society. Source

Linda M.F.,University of Calgary
American Journal of Primatology | Year: 2010

Field primatologists face unusual ethical issues. We study animals rather than people and receive research approval from animal care rather than ethics committees. However, animal care evaluation forms are developed from concerns about laboratory animal research and are based on the "Three R's" for humane treatment of captive experimental subjects (replacement, reduction and refinement), which are only debatably relevant to field research. Scientists who study wild, free-ranging primates in host countries experience many ethical dilemmas seldom dealt with in animal care forms. This paper reviews the ethical issues many field primatologists say they face and how these might be better addressed by animal care forms. The ethical issues arising for field researchers are divided into three categories: "Presence, Protocols and People" and for each the most frequent issues are described. The most commonly mentioned ethical concern arising from our presence in the field is the possibility of disease transmission. Although most primate field studies employ only observational protocols, the practice of habituating our study animals to close human presence is an ethical concern for many since it can lessen the animals' fear of all humans, thereby facilitating undesirable behaviors (e.g., crop-raiding) and rendering them vulnerable to harm. Field primatologists who work in host countries must observe national laws and local traditions. As conservationists, primatologists must often negotiate between the resource needs and cultural practices of local people and the interests of the nonhuman primates. Many say they face more ethical dilemmas arising from human interactions than from research on the animals per se. This review concludes with suggestions for relevant questions to ask on animal care forms, and actions that field primatologists can take to better inform animal care committees about the common ethical issues we experience as well as how to develop guidelines for addressing them. ©2010 Wiley-Liss, Inc. Source

Miller R.J.H.,University of Calgary
Current Opinion in Cardiology | Year: 2015

RECENT FINDINGS: Three randomized trials were reviewed: the Effect of spironolactone on diastolic function and exercise capacity in patients with heart failure with preserved ejection fraction: the Aldo-DHF randomized controlled trial; the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist trial; and its echocardiography substudy. The Aldo-DHF trial showed improvements in echocardiographic measures of diastolic function. In the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist trial, hospitalization for heart failure was significantly reduced with MRA therapy with no difference in the primary outcome of cardiovascular death or hospitalization. In patients with high risk, however, there may be a reduction in cardiovascular mortality. We will also briefly discuss finerenone, a new generation MRA associated with a lower incidence of hyperkalemia.SUMMARY: New evidence shows that MRA therapy decreases left ventricular mass and left atrial size, reduces hospitalization, and may reduce cardiovascular mortality in patients with high risk.PURPOSE OF REVIEW: The majority of randomized clinical trials in heart failure with preserved ejection fraction (HFpEF) have failed to show meaningful improvements in clinical outcomes. Recent randomized trials have shown benefits from mineralocorticoid receptor antagonists (MRAs) in the management of HFpEF. This review will focus on new evidence for MRA therapy in patients with HFpEF. © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins Source

Zamponi G.W.,University of Calgary
Nature Reviews Drug Discovery | Year: 2016

Voltage-gated calcium channels are important regulators of brain, heart and muscle functions, and their dysfunction can give rise to pathophysiological conditions ranging from cardiovascular disorders to neurological and psychiatric conditions such as epilepsy, pain and autism. In the nervous system, calcium channel blockers have been used successfully to treat absence seizures, and are emerging as potential therapeutic avenues for pathologies such as pain, Parkinson disease, addiction and anxiety. This Review provides an overview of calcium channels as drug targets for nervous system disorders, and discusses potential challenges and opportunities for the development of new clinically effective calcium channel inhibitors. © 2016 Macmillan Publishers Limited. All rights reserved. Source

Gour G.,University of Calgary
Physical Review Letters | Year: 2010

We discover a simple factorization law describing how multipartite entanglement of a composite quantum system evolves when one of the subsystems undergoes an arbitrary physical process. This multipartite entanglement decay is determined uniquely by a single factor we call the entanglement resilience factor. Since the entanglement resilience factor is a function of the quantum channel alone, we find that multipartite entanglement evolves in exactly the same way as bipartite (two qudits) entanglement. For the two qubits case, our factorization law reduces to the main result of. In addition, for a permutation P, we provide an operational definition of P asymmetry of entanglement, and find the conditions when a permuted version of a state can be achieved by local means. © 2010 The American Physical Society. Source

Rolian C.,University of Calgary | Gordon A.D.,University at Albany
American Journal of Physical Anthropology | Year: 2013

Previous analyses of hand morphology in Australopithecus afarensis have concluded that this taxon had modern human-like manual proportions, with relatively long thumbs and short fingers. These conclusions are based on the A.L.333 composite fossil assemblage from Hadar, Ethiopia, and are premised on the ability to assign phalanges to a single individual, and to the correct side and digit. Neither assignment is secure, however, given the taphonomy and sample composition at A.L.333. We use a resampling approach that includes the entire assemblage of complete hand elements at Hadar, and takes into account uncertainties in identifying phalanges by individual, side and digit number. This approach provides the most conservative estimates of manual proportions in Au. afarensis. We resampled hand long bone lengths in Au. afarensis and extant hominoids, and obtained confidence limits for distributions of manual proportions in the latter. Results confirm that intrinsic manual proportions in Au. afarensis are dissimilar to Pan and Pongo. However, manual proportions in Au. afarensis often fall at the upper end of the distribution in Gorilla, and very lower end in Homo, corresponding to disproportionately short thumbs and long medial digits in Homo. This suggests that manual proportions in Au. afarensis, particularly metacarpal proportions, were not as derived towards Homo as previously described, but rather are intermediate between gorillas and humans. Functionally, these results suggest Au. afarensis could not produce precision grips with the same efficiency as modern humans, which may in part account for the absence of lithic technology in this fossil taxon. Am J Phys Anthropol 152:393-406, 2013. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc. Source

Liao W.,University of Calgary
International Journal for Numerical Methods in Fluids | Year: 2010

A fourth-order compact finite-difference method is proposed in this paper to solve the system of two-dimensional Burgers' equations. The new method is based on the two-dimensional Hopf-Cole transformation, which transforms the system of two-dimensional Burgers' equations into a linear heat equation. The linear heat equation is then solved by an implicit fourth-order compact finite-difference scheme. A compact fourth-order formula is also developed to approximate the boundary conditions of the heat equation, while the initial condition for the heat equation is approximated using Simpson's rule to maintain the overall fourth-order accuracy. Numerical experiments have been conducted to demonstrate the efficiency and high-order accuracy of this method. © 2009 John Wiley & Sons, Ltd. Source

Marshall S.J.,University of Calgary
Hydrology and Earth System Sciences | Year: 2014

Observations of high-elevation meteorological conditions, glacier mass balance, and glacier run-off are sparse in western Canada and the Canadian Rocky Mountains, leading to uncertainty about the importance of glaciers to regional water resources. This needs to be quantified so that the impacts of ongoing glacier recession can be evaluated with respect to alpine ecology, hydroelectric operations, and water resource management. In this manuscript the seasonal evolution of glacier run-off is assessed for an alpine watershed on the continental divide in the Canadian Rocky Mountains. The study area is a headwaters catchment of the Bow River, which flows eastward to provide an important supply of water to the Canadian prairies. Meteorological, snowpack, and surface energy balance data collected at Haig Glacier from 2002 to 2013 were analysed to evaluate glacier mass balance and run-off. Annual specific discharge from snow- and ice-melt on Haig Glacier averaged 2350 mm water equivalent from 2002 to 2013, with 42% of the run-off derived from melting of glacier ice and firn, i.e. water stored in the glacier reservoir. This is an order of magnitude greater than the annual specific discharge from non-glacierized parts of the Bow River basin. From 2002 to 2013, meltwater derived from the glacier storage was equivalent to 5-6% of the flow of the Bow River in Calgary in late summer and 2-3% of annual discharge. The basin is typical of most glacier-fed mountain rivers, where the modest and declining extent of glacierized area in the catchment limits the glacier contribution to annual run-off. © Author(s) 2014. Source

Wong C.L.,University of Toronto | Holroyd-Leduc J.,University of Calgary | Simel D.L.,Duke University | Straus S.E.,University of Toronto
JAMA - Journal of the American Medical Association | Year: 2010

Context: Delirium occurs in many hospitalized older patients and has serious consequences including increased risk for death and admission to long-term care. Despite its importance, health care clinicians often fail to recognize delirium. Simple bedside instruments may lead to improved identification. Objective: To systematically review the evidence on the accuracy of bedside instruments in diagnosing the presence of delirium in adults. Data Sources: Search of MEDLINE (from 1950 to May 2010), EMBASE (from 1980 to May 2010), and references of retrieved articles to identify studies of delirium among in-patients. Study Selection: Prospective studies of diagnostic accuracy that compared at least 1 delirium bedside instrument to the Diagnostic and Statistical Manual of Mental Disorders - based diagnosis made by a geriatrician, psychiatrist, or neurologist. Data Synthesis: There were 6570 unique citations identified with 25 prospectively conducted studies (N=3027 patients) meeting inclusion criteria and describing use of 11 instruments. Positive results that suggested delirium with likelihood ratios (LRs) greater than 5.0 were present for the Global Attentiveness Rating (GAR), Memorial Delirium Assessment Scale (MDAS), Confusion Assessment Method (CAM), Delirium Rating Scale Revised-98 (DRS-R-98), Clinical Assessment of Confusion (CAC), and Delirium Observation Screening Scale (DOSS). Normal results that decreased the likelihood of delirium with LRs less than 0.2 were calculated for the GAR, MDAS, CAM, DRS-R-98, Delirium Rating Scale (DRS), DOSS, Nursing Delirium Screening Scale (Nu-DESC), and Mini-Mental State Examination (MMSE). The Digit Span test and Vigilance "A" test in isolation have limited utility in diagnosing delirium. Considering the instrument's ease of use, test performance, and clinical importance of the heterogeneity in the confidence intervals (CIs) of the LRs, the CAM has the best available supportive data as a bedside delirium instrument (summary-positive LR, 9.6; 95% CI, 5.8-16.0; summary-negative LR, 0.16; 95% CI, 0.09-0.29). Of all scales, the MMSE (score <24) was the least useful for identifying a patient with delirium (LR, 1.6; 95% CI, 1.2-2.0). Conclusion: The choice of instrument may be dictated by the amount of time available and the discipline of the examiner; however, the best evidence supports use of the CAM, which takes 5 minutes to administer. ©2010 American Medical Association. All rights reserved. Source

Wiltshire K.M.,University of Calgary
Neuromuscular disorders : NMD | Year: 2013

Autosomal recessive Emery Dreifuss muscular dystrophy (AR-EDMD) is rare, with few reports in the medical literature. We describe the first cases of AR-EDMD and autosomal dominant familial partial lipodystrophy (FPLD) in the Hutterite population resulting from homozygous or heterozygous R482Q mutations in the lamin A/C gene (LMNA). Heterozygosity for LMNA R482Q mutation causes FPLD, which is associated with increased risk of hyperlipidemia and hypertension. The overall carrier frequency of the R482Q mutation in Dariusleut and Leherleut Hutterites in Alberta was found to be 1.45%. Homozygosity for this mutation has not been previously reported and here resulted in a combination of generalized lipodystrophy and EDMD. Knowledge that the LMNA R482Q mutation is present in this population is important for genetic counseling, surveillance, and management of the associated disorders. Copyright © 2012 Elsevier B.V. All rights reserved. Source

Ross S.A.,University of Calgary
Current Medical Research and Opinion | Year: 2015

Objective: Current type 2 diabetes (T2D) treatment guidelines include weight maintenance or loss, avoidance of hypoglycemia, and targets for blood pressure and circulating lipids, in addition to glycemic control. Increasingly, clinical trials and meta-Analyses employ composite endpoints to capture the net clinical benefit of a given T2D intervention. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) represent a new class of injected antihyperglycemic agents that may be well suited to reaching many of these targets among patients failing on metformin monotherapy.Research designs and methods: Using MEDLINE, Embase and Google Scholar, studies were sought that employed composite endpoints and that reported outcomes with exenatide and/or liraglutide. Bibliographies of relevant review articles were consulted to search for additional reports.Results: Many trials have used the combination of HbA1c <7%, no weight gain and no hypoglycemic episodes as the composite endpoint in evaluating T2D therapies; however, at least 15 other distinct composite endpoints have been reported. Findings were relatively consistent across studies, regardless of how the composite endpoint was defined. Specifically, the GLP-1 RAs appear to be superior to other agents in their efficacy in providing T2D patients failing on metformin with a net clinical benefit, which can include avoidance of hyperglycemia and maintenance or improvement in body weight.Conclusions: Use of composite endpoints represents an important advance in T2D. While no single such endpoint has achieved dominance in the field, widely used composite endpoints capture efficacy in glycemic control as well as safety and effects on markers of cardiovascular risk. © 2015 Informa UK Ltd. Source

Lau D.C.,University of Calgary
Primary care diabetes | Year: 2010

Diabetes has become the tsunami of non-communicable chronic diseases, with its alarmingly high prevalence largely driven by the global obesity epidemic. Achieving a healthy weight and preventing weight gain are integral components of optimal diabetes management. A modest weight loss of 5-10% is associated with significant reduction in blood sugar, lipid and blood pressure levels. Insulin detemir is an effective basal insulin analogue associated with less weight gain compared with both insulin NPH and insulin glargine. Once-daily insulin detemir could be considered an effective therapy for people with type 2 diabetes on lifestyle interventions and oral anti-diabetic agent therapy who require insulin. 2010 Primary Care Diabetes Europe. Published by Elsevier Ltd.. All rights reserved. Source

Objective: To determine the utility of substitution of pregabalin (PGB) for gabapentin (GBP) therapy in the relief of neuropathic pain (NeP) in patients with peripheral neuropathy (PN). Design: A cohort study was performed examining PGB substitution in patients who were GBP responders (≥30% NeP relief on a visual analog scale [VAS]) or GBP nonresponders after prolonged GBP use, with further comparison to patients receiving continuous GBP therapy. Setting: Patients with PN and related NeP requiring GBP therapy were evaluated in a tertiary care neurological clinic at 0, 6, and 12 months. Outcome Measures: Pain severity (Visual Analog Score [VAS]) was the primary outcome measure, while quality of life (European Quality of Life - 5 Domains [EQ-5D] and EQ-5D VAS) and occurrence of adverse events were secondary outcome measures. Results: Both GBP responder and nonresponder groups had additional NeP relief of about 25% following substitution of PGB after 6 and 12 months, while improved EQ-5D VAS was identified in the GBP nonresponder group. There were no serious adverse events for either medication, while GBP nonresponders discontinued PGB in more than 30% of cases due to inefficacy or adverse events. Conclusions: Randomized, controlled, blinded head-to-head studies of GBP and PGB have not been published. The results of this open-label assessment of PGB substitution for GBP suggest that PGB may provide additional pain relief and possible improvement in quality of life above that received by GBP use in patients with NeP due to PN. © 2010 American Academy of Pain Medicine. Source

Appropriate methods should be employed to enhance the oil recovery from the Naturally Fractured Reservoirs (NFRs). One of the candidates for enhancing the oil recovery from these reservoirs is the surfactant-based chemical flooding. This paper highlights the technical achievements and challenges of the chemical flooding in the NFRs. The classification, production characteristics, recovery mechanisms of the NFRs and significant findings of the chemical flooding in these reservoirs are reviewed and analyzed. It is expected that this paper will serve as a helpful reference tool for the engineers interested in chemical flooding in the NFRs. © 2011, IFP Energies nouvelles. Source

Becker W.J.,University of Calgary
Headache | Year: 2013

Cluster headache pain is very intense, usually increases in intensity very rapidly from onset, and attacks are often frequent. These clinical features result in significant therapeutic challenges. The most effective pharmacological treatment options for acute cluster attack include subcutaneous sumatriptan, 100% oxygen, and intranasal zolmitriptan. Subcutaneous or intramuscular dihydroergotamine and intranasal sumatriptan are additional options. Transitional therapy is applicable mainly for patients with high-frequency (>2 attacks per day) episodic cluster headache, and options include short courses of high-dose oral corticosteroids, dihydroergotamine, and occipital nerve blocks with local anesthetic and steroids. Prophylactic therapy is important both for episodic and chronic cluster headache, and the main options are verapamil and lithium. Verapamil is drug of first choice but may cause cardiac arrhythmias, and periodic electrocardiograms (EKGs) during dose escalation are important. Many other drugs are also in current use, but there is an insufficient evidence base to recommend them. © 2013 American Headache Society. Source

Boiko I.,University of Calgary
Journal of the Franklin Institute | Year: 2010

Estimation precision and bandwidth of sliding mode (SM) observers are analyzed in the frequency domain for different settings of the observer design parameters. It was shown previously that the SM observer could be analyzed as a relay feedback-feedforward system. It is feedback with respect to the measured variable of the system being observed, and feedforward with respect to the control applied to the system being observed. This approach is now further extended to analysis of effects of design parameter change on observer performance. An example of SM observer design for estimation of DC motor speed from the measurements of armature current is considered in the paper. The input- output properties of observer dynamics are analyzed with the use of the locus of a perturbed relay system (LPRS) method. © 2009 The Franklin Institute. Published by Elsevier Ltd. All rights reserved. Source

Laupland K.B.,University of Calgary
Clinical Microbiology and Infection | Year: 2013

Bloodstream infection (BSI) is associated with major morbidity and mortality. Population-based studies are the optimal designs to determine the occurrence of BSI. This is because in these designs all cases of BSI occurring in residents of a defined population are included, and where the population at risk is known incidence rates may be determined. Furthermore, selection bias is minimized by inclusion of all cases fulfilling the case definition. Despite the methodological advantages, there is only a small body of published literature investigating BSI at the population level. Few studies conducted since the 1970s have included all aetiologies of BSI and have reported rates between 80 and 189 per 100 000 per year with higher rates reported in more recent years. The three most common aetiologies of BSI are Escherichia coli, Staphylococcus aureus and Streptococcus pneumoniae, which occur at approximate rates of 35, 25 and 10 per 100 000 population, respectively. The incidence of BSI has been demonstrated to vary significantly among regions, and this is in part related to blood culturing rates, population demographic differences and risk factor distribution in regions. Knowledge of the incidence of BSI is important for setting healthcare and research priorities and for evaluating the effectiveness of preventative interventions. © 2013 The Authors. Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases. Source

Kirton A.,University of Calgary | De Veber G.,University of Toronto
Stroke | Year: 2013

Life after perinatal stroke can certainly be good. The high level of functioning attained by many children despite large brain lesions is a remarkable testament to the potential power of developmental plasticity. However, it is clear that such early injury places many other children on an abnormal developmental trajectory with functional consequences. How the interplay of multiple disordered functions in individual children may combine to impact the eventual outcome is of great interest. A child with great developmental potential may be stymied by pathological electrographic brain activity during sleep. Another child highly capable of acquiring new motor skills may fail to gain practical function because proprioceptive deficits prevent him or her from knowing where his or her hand is in space. Another with normal intelligence but an attention disorder may not be able to engage in school, therapy, or sports that could each improve function. With improving recognition and measurement, an integrated understanding of how these multiple factors dictate outcomes in individual children will be a major challenge of perinatal stroke research going forward. Source

Oil sands transportation diversification is important for preventing discounted crude pricing. Current life cycle assessment (LCA) models that assess greenhouse gas (GHG) emissions from crude oil transportation are linearly-scale and fail to account for project specific details. This research sets out to develop a detailed LCA model to compare the energy inputs and GHG emissions of pipeline and rail transportation for oil sands products. The model is applied to several proposed oils sands transportation routes that may serve as future markets. Comparison between transportation projects suggest that energy inputs and GHG emissions show a high degree of variation. For both rail and pipeline transportation, the distance over which the product is transported has a large impact on total emissions. The regional electricity grid and pump efficiency have the largest impact on pipeline emissions, while train engine efficiency and bitumen blending ratios have the largest impact on rail transportation emissions. LCA-based GHG regulations should refine models to account for the range of product pathways and focus efforts on cost-effective emission reductions. As the climate-change impacts of new oil sands transportation projects are considered, GHG emission boundaries should be defined according to operation control. © 2013 Elsevier Ltd. Source

Harder L.D.,University of Calgary | Aizen M.A.,National University of Comahue
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010

Pollen limitation (PL) of seed production creates unique conditions for reproductive adaptation by angiosperms, in part because, unlike under ovule or resource limitation, floral interactions with pollen vectors can contribute to variation in female success. Although the ecological and conservation consequences of PL have received considerable attention in recent times, its evolutionary implications are poorly appreciated. To identify general influences of PL on reproductive adaptation compared with those under other seed-production limits and their implications for evolution in altered environments, we derive a model that incorporates pollination and postpollination aspects of PL. Because PL always favours increased ovule fertilization, even when population dynamics are not seed limited, it should pervasively influence selection on reproductive traits. Significantly, under PL the intensity of inbreeding does not determine whether outcrossing or autonomous selfing can evolve, although it can affect which response is most likely. Because the causes of PL are multifaceted in both natural and anthropogenically altered environments, the possible outcrossing solutions are diverse and context dependent, which may contribute to the extensive variety of angiosperm reproductive characteristics. Finally, the increased adaptive options available under PL may be responsible for positive global associations between it and angiosperm diversity. © 2010 The Royal Society. Source

Ronksley P.E.,University of Calgary
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association | Year: 2012

Administrative data are commonly used for surveillance of chronic medical conditions. The purpose of this study was to determine the validity of an algorithm derived from administrative data for identifying chronic kidney disease (CKD) compared to the reference standard of estimated glomerular filtration rate (eGFR). We identified adults from the province of Alberta with at least two outpatient serum creatinine measurements within a 1-year time period. Validity indices were estimated for CKD using up to 3 years of administrative data (physician billing claims and hospital discharge abstracts) for various case-definition combinations. For each algorithm, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated against two reference standard definitions of CKD (two eGFR measurements <60 mL/min/1.73m(2) or mean eGFR < 30 mL/min/1.73m(2)). A total of 321 293 eligible subjects were identified. Irrespective of the algorithm, sensitivities for defining CKD (eGFR < 60 mL/min/1.73m(2)) using administrative codes were low. A case-definition algorithm employing two physician claims or one hospitalization within a 2-year period had sensitivity of 19.4%, specificity of 97.2%, PPV of 60.1% and NPV of 84.8% for detecting CKD. Estimates of sensitivity were higher when <30 mL/min/1.73m(2) was used as the reference standard, although PPVs were lower and consistently less than 50%. These results, using eGFR as a reference standard, suggest that administrative data have insufficient sensitivity and PPV for CKD surveillance, although they may be useful when highly specific algorithms are required for research purposes. Source

He Z.,University of Calgary
Sensors (Basel, Switzerland) | Year: 2013

Dead-reckoning (DR) algorithms, which use self-contained inertial sensors combined with gait analysis, have proven to be effective for pedestrian navigation purposes. In such DR systems, the primary error is often due to accumulated heading drifts. By tightly integrating global navigation satellite system (GNSS) Doppler measurements with DR, such accumulated heading errors can usually be accurately compensated. Under weak signal conditions, high sensitivity GNSS (HSGNSS) receivers with block processing techniques are often used, however, the Doppler quality of such receivers is relatively poor due to multipath, fading and signal attenuation. This often limits the benefits of integrating HSGNSS Doppler with DR. This paper investigates the benefits of using Doppler measurements from a novel direct vector HSGNSS receiver with pedestrian dead-reckoning (PDR) for indoor navigation. An indoor signal and multipath model is introduced which explains how conventional HSGNSS Doppler measurements are affected by indoor multipath. Velocity and Doppler estimated by using direct vector receivers are introduced and discussed. Real experimental data is processed and analyzed to assess the veracity of proposed method. It is shown when integrating HSGNSS Doppler with PDR algorithm, the proposed direct vector method are more helpful than conventional block processing method for the indoor environments considered herein. Source

Mohammadi H.,University of Calgary
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2011

The main problem with polymeric heart valves (which are already biocompatible) is that they usually fail in the long term owing to tearing and calcification of the leaflets under high dynamic tensile bending stress and oxidative reactions with blood. To overcome this shortcoming, it is hypothesized that synthetic valve leaflets which mimic native valve leaflet structure fabricated from fibre-reinforced composite material will optimize leaflet stresses and decrease tears and perforations. The objective of this study is to develop a PVA-BC (polyvinyl alcohol-bacterial cellulose)-based hydrogel that mimics not only the non-linear mechanical properties displayed by porcine heart valves, but also their anisotropic behaviour. By applying a controlled strain to the PVA samples, while undergoing low-temperature thermal cycling, it was possible to create oriented mechanical properties in PVA hydrogels. The oriented stress-strain properties of porcine aortic valves were matched simultaneously by a PVA hydrogel (15 per cent PVA, 0.5 BC cycle 4, 75 per cent initial tensile strain). This novel technique allows the control of anisotropy to PVA hydrogel, and gives a broad range of control of its mechanical properties, for specific medical device applications. © Authors 2011. Source

Fritzler M.J.,University of Calgary
Lupus | Year: 2013

The recently concluded Tenth International Congress on Systemic Lupus Erythematosus (SLE) held in Buenos Aires was a resounding success. This overview summarizes some of the origins of the First International Congress held in Calgary, Canada in 1986, predictions offered by past Congress Presidents, and a perspective on the trends in autoantibody testing, which remains one of the key approaches to the early and accurate diagnosis of SLE. The last few decades have witnessed a remarkable proliferation of new diagnostic technologies including addressable laser bead immunoassays and, more recently, chemiluminescence and lateral flow technologies that could find a clinical niche in point-of-care diagnostics. Against the backdrop of these constantly emerging technologies, indirect immunofluorescence has remained the platform of choice for many laboratories and diagnosticians. The notion that autoantibodies are pathogenic has been challenged by evidence that some autoantibodies are protective, some may have catalytic capacity while others may be neutral or have no function at all. The latter notion of functionless or "junk" autoantibodies needs to be taken under some advisement, because there was a time when a great proportion of the human genome was considered to include "junk DNA". The butterfly as a symbol of hope and progress in SLE research over the past 27 years since the First International Congress on SLE is almost certainly to be even more appropriate when future Congresses are held in Geneva (2015), Melbourne (2017) and eventually one in 2050. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav. Source

Kaplan G.G.,University of Calgary
American Journal of Gastroenterology | Year: 2016

The TABACROHN Study Group conducted a multicenter prospective cohort study, demonstrating that smoking cessation improved the prognosis of Crohn's disease. Patients who continued to smoke were 50% more likely to relapse compared with non-smokers. Smoking cessation reduced the risk of flaring, regardless of exposure to anti-tumor necrosis factor agents. Despite the evidence that smoking cessation is beneficial, many patients do not quit smoking after their diagnosis of Crohn's disease. Lack of awareness, physical addiction, and social context of smoking inhibit smoking cessation. In spite of this, comprehensive smoking cessation programs have been shown to be effective and reduce costs. © 2016 by the American College of Gastroenterology. Source

Friedrich M.G.,Montreal Heart Institute | Friedrich M.G.,University of Calgary | Karamitsos T.D.,University of Oxford
Journal of Cardiovascular Magnetic Resonance | Year: 2013

Oxygenation-sensitive cardiovascular magnetic resonance (CMR) is a non-contrast technique that allows the non-invasive assessment of myocardial oxygenation. It capitalizes on the fact that deoxygenated hemoglobin in blood can act as an intrinsic contrast agent, changing proton signals in a fashion that can be imaged to reflect the level of blood oxygenation. Increases in O2 saturation increase the BOLD imaging signal (T2 or T2*), whereas decreases diminish it. This review presents the basic concepts and limitations of the BOLD technique, and summarizes the preclinical and clinical studies in the assessment of myocardial oxygenation with a focus on recent advances. Finally, it provides future directions and a brief look at emerging techniques of this evolving CMR field. © 2013 Friedrich and Karamitsos; licensee BioMed Central Ltd. Source

Eggermont J.J.,University of Calgary | Roberts L.E.,McMaster University
Cell and Tissue Research | Year: 2015

Chronic tinnitus (ringing of the ears) is a medically untreatable condition that reduces quality of life for millions of individuals worldwide. Most cases are associated with hearing loss that may be detected by the audiogram or by more sensitive measures. Converging evidence from animal models and studies of human tinnitus sufferers indicates that, while cochlear damage is a trigger, most cases of tinnitus are not generated by irritative processes persisting in the cochlea but by changes that take place in central auditory pathways when auditory neurons lose their input from the ear. Forms of neural plasticity underlie these neural changes, which include increased spontaneous activity and neural gain in deafferented central auditory structures, increased synchronous activity in these structures, alterations in the tonotopic organization of auditory cortex, and changes in network behavior in nonauditory brain regions detected by functional imaging of individuals with tinnitus and corroborated by animal investigations. Research on the molecular mechanisms that underlie neural changes in tinnitus is in its infancy and represents a frontier for investigation. © 2014, The Author(s). Source

Walker L.M.,University of Calgary | Robinson J.W.,Tom Baker Cancer Center
Qualitative Health Research | Year: 2012

More than half of all men with prostate cancer will be treated with androgen deprivation therapy (ADT) at some point during their lives. Though an effective treatment for prostate cancer, ADT results in profound changes in the man's sense of masculinity and sexuality (e.g., erectile dysfunction, loss of libido, genital atrophy and severe genital shrinkage, hot flashes, loss of muscle mass, fatigue, bodily feminization). These changes usually result in the cessation of all sexual activity. Surprisingly, some couples do find ways of continuing to have satisfying sex despite the man's castrate level of testosterone. Herein, we describe the sexual struggles that couples encounter when attempting to adapt sexually to ADT. A grounded theory methodology was used to analyze interview data. The successful strategies that couples used to overcome struggles, as well as those which seemed to exacerbate struggles, are documented. Couples adjusting to ADT might benefit from knowing which strategies are most likely to result in positive adjustment and which are not. © 2012 SAGE Publications. Source

Wiebe S.,University of Calgary
Nature Reviews Neurology | Year: 2012

Predicting response to therapy in individual patients with epilepsy is not straightforward. An exploration of long-term surgical outcomes in an epilepsy cohort has identified seven patterns of remission and relapse, and the probability of each outcome has been calculated. The study provides new predictors of postoperative outcomes in epilepsy. © 2012 Macmillan Publishers Limited. All rights reserved. Source

Elliott C.,University of Calgary
Social Science and Medicine | Year: 2014

In light of its influence on food preferences, purchase requests and consumption patterns, food marketing-particularly for unhealthy foods-has been increasingly recognized as a problem that affects the health of young people. This has prompted both a scrutiny of the nutritional quality of food products and various interventions to promote healthy eating. Frequently overlooked by the public health community, however, is the symbolic and social meaning of food for teenagers. Food has nutritive value, but it has symbolic value as well-and this qualitative study explores the meaning of non-branded foods for teenagers. Inspired by the construct of brand personality, we conduct focus groups with 12-14 year olds in to probe their perspectives on the "food personalities" of unbranded/commodity products and categories of food. Despite the lack of targeted marketing/promotional campaigns for the foods discussed, the focus groups found a remarkable consensus regarding the characteristics and qualities of foods for young people. Teenagers stigmatize particular foods (such as broccoli) and valorize others (such as junk food), although their discussions equally reveal the need to consider questions beyond that of social positioning/social status. We suggest that public health initiatives need to focus greater attention on the symbolic aspects of food, since a focus on nutritional qualities does not unveil the other significant factors that may make foods appealing, or distasteful, to young people. © 2014 Elsevier Ltd. Source

Davison K.M.,University of Calgary
Eating Behaviors | Year: 2013

To help address gaps in information about the links that exist between psychiatric medications and weight changes, an investigation of relationships among select psychotropic agents (i.e., mood stabilizers, antidepressants, and second-generation antipsychotics {SGAs}), eating behaviors, and weight was conducted. Data from a cross-sectional study of food habits in 97 individuals with mood disorders was used. Variables measured included use of psychotropic agents, measures of cognitive dietary restraint and disinhibition from the Three Factor Eating Behavior Questionnaire (TFEQ), psychiatric functioning, reported weight gain and measured BMI. The TFEQ measures were compared to population norms. Bivariate and multivariate analyses examined the relationships among the psychotropic agents, eating behaviors, and weight. Indicators of cognitive dietary restraint and disinhibition were higher than population norms (p's < 0.05 to 0.0001). Depression was associated with restraint (rho = 0.21, p < 0.05). BMI was associated with disinhibition (p < 0.05); antidepressant use appeared to moderate weight for those taking SGAs and mood stabilizers (p < 0.05). Exploration of the interacting mechanisms of psychotropic agents and attention to eating attitudes and behaviors of individuals taking psychiatric medications might lessen pharmaceutical-induced weight gain. Prospective research on large samples that can make comparisons to those who are untreated is needed. © 2013. Source

Vogel H.J.,University of Calgary
Biochemistry and Cell Biology | Year: 2012

Lactoferrin is an abundant iron-binding protein in milk. This 80 kDa bilobal glycoprotein is also present in several other secreted bodily fluids, as well as in the secondary granules of neutrophils. The potent iron-binding properties of lactoferrin can locally create iron deficiency, and this is an important factor in host defense as it prevents bacteria from growing and forming biofilms. In addition to having antibacterial activity, lactoferrin is now known to have a long list of other beneficial biological properties. It has direct antiviral, antifungal, and even some anticancer activities. It can also promote wound healing and bone growth, or it can act as an iron carrier. Moreover, lactoferrin displays a cytokine-like "alarmin" activity, and it activates the immune system. Simultaneously, it can bind endotoxin (lipopolysaccharide), and in doing so, it modulates the activity of the host immune response. The majority of these intriguing biological activities reside in the unique positively charged N-terminal region of the protein. Interestingly, several peptides, which retain many of the beneficial activities, can be released from this region of lactoferrin. An isoform of the human protein, known as delta-lactoferrin, is expressed inside many cells, where it acts as a transcription factor. Lactoferrin purified from human and bovine milk have very similar but not completely identical properties. Lactoferrin receptors have been identified on the surface of various cells, and some of these can bind both the human and the bovine protein. Because of the extensive health-promoting effects of lactoferrin, there has been considerable interest in the use of bovine or human lactoferrin as a "protein nutraceutical" or as a therapeutic protein. When lactoferrin is used as a "biologic drug", it seems to be orally active in contrast to most other therapeutic proteins. © 2011 Published by NRC Research Press. Source

Miller M.S.,University of Southern California | Eaton D.W.,University of Calgary
Geophysical Research Letters | Year: 2010

Delineating mantle interfaces can provide important clues for understanding the formation of continents. We use S-wave receiver functions to investigate lithospheric structure along a transect extending from Vancouver Island to Baffin Island. Observed Sp converted waves allow for interpretation of boundaries in the depth range expected for tectonic plates. Receiver functions show a distinct negative amplitude feature, interpreted as the lithosphere-asthenosphere boundary, at shallow depths beneath British Columbia (∼85km), deepening abruptly at the eastern edge of the Cordillera to ∼260km beneath the Canadian Shield. Dipping mid-lithospheric discontinuities extend beneath several giant ca. 1.8 Ga epicontinental magmatic arcs, consistent with formation of cratonic lithosphere by arc accretion. This model provides a plausible explanation for global mid-lithospheric discontinuities within cratons and aids in understanding their formation. © 2010 by the American Geophysical Union. Source

Westwick D.T.,Vrije Universiteit Brussel | Westwick D.T.,University of Calgary | Schoukens J.,Vrije Universiteit Brussel
Automatica | Year: 2012

The iterative optimizations often used to identify Wiener-Hammerstein models, pairs of linear filters separated by memoryless nonlinearities, require good initial estimates of the linear elements in order to avoid them getting caught in local minima. Previous work has shown that initial estimates of the two linear elements can be formed by splitting the poles and zeros of the best linear approximation of the Wiener-Hammerstein system between the two linear elements, an approach which can generate a large number of initializations. This paper develops a scanning technique that can efficiently evaluate each of the proposed initializations using estimates of some carefully constructed nonlinear characteristics of the system, estimates which can be formed using linear system identification techniques after some data pre-processing. This approach results in a much smaller number, often only one, of potential starting points for the optimization. The proposed algorithm is demonstrated using a Monte Carlo simulation using data from the SYSID 2009 Wiener-Hammerstein Benchmark system. © 2012 Elsevier Ltd. All rights reserved. Source

Federico S.,University of Calgary
International Journal of Non-Linear Mechanics | Year: 2012

This work aims at obtaining a covariant representation of the elasticity tensor of a hyperelastic material when the elastic strain energy potential is written employing the volumetricdistortional decomposition of the deformation. This requires the careful definition of some fundamental fourth-order tensors: the identity, the spherical operator, and the deviatoric operator, which appear in the material and spatial expressions of the elasticity tensor. These operators can be defined in the spatial or the material setting and admit pulled-back and pushed-forward forms, respectively. These forms are intimately related to the pulled-back and pushed-forward metric tensors, and are somewhat awkward to derive in Cartesian coordinates, because of the loss of the distinction between a vector space and its dual, and therefore between objects having contravariant and covariant components, which obey to different transformation laws. The relationship between the deformation and the various forms of the identity, spherical, and deviatoric operators can be entirely clarified only within a covariant theory, where the central role played by the spatial and material metric tensors, and their pulled-back and pushed-forward counterparts, which are deformation tensors, can be emphasised. © 2011 Elsevier Ltd. All rights reserved. Source

Toth C.,University of Calgary
Expert Opinion on Drug Safety | Year: 2012

Introduction: Pregabalin is an anticonvulsant with one known mechanism of action which is used most specifically in the management of neuropathic pain. Areas covered: The adverse effect profile of this medication from controlled, randomized studies as well as open and long-term studies is described with consideration of the evidence-based results for pregabalin's clinical use. Expert opinion: Pregabalin is a mostly well tolerated medication for the management of neuropathic pain and other conditions. Pregabalin use is associated with benign central nervous system and systemic adverse effects with very limited metabolic, idiosyncratic, or teratogenic adverse effects. Understanding of these adverse effects is essential for the clinician treating the patient and for the patient receiving treatment. Sedation, dizziness, peripheral edema, and dry mouth are the most prevalent adverse events experienced in all clinical populations. Other adverse effects are rare, but are discussed. © 2012 Informa UK, Ltd. Source

Mars M.,University of KwaZulu - Natal | Scott R.E.,University of Calgary
Health Affairs | Year: 2010

E-health (information and communication technology that facilitates health and health care) is expanding in developed, developing, and least-developed countries. E-health's ability to transcend sociopolitical boundaries holds the potential to create a borderless world for health systems and health care delivery. But the policy needed to guide e-health development is limited and just now emerging in developed countries. What's needed to foster e-health growth in the developing world is thoughtful policy to facilitate patient mobility and data exchange, across both international borders and regional boundaries within countries. © 2010 Project HOPE-The People-to-People Health Foundation, Inc. Source

Lai D.W.L.,University of Calgary
Journal of Cross-Cultural Gerontology | Year: 2012

In Canada's multicultural society, ethnic identity is important to the elderly and can influence areas such as access to services, health promotion and care. Often, the complex nature of ethnic identity is underestimated when looking at cultural groups. This study aims to: (a) validate the factor structure of a Chinese ethnic identity measure for older Chinese in Canada, (b) examine the level of ethnic identity of the participants, and (c) examine the correlates of ethnic identity in these older individuals. Using data from a large, national research project on the elderly Chinese in Canada, this study analyzed the results gathered from a total of 2,272 participants. Principal component analysis, maximum-likelihood confirmatory factor analysis, and multiple regression analysis were performed. The results indicated that ethnic identity of the older Chinese is a multi-dimensional construct made up of three factors: (a) culture related activities, (b) community ties, (c) linkage with country of origin, and (d) cultural identification. The findings have provided a better understanding of how ethnic identity can be measured among the aging Chinese population in Canada. © 2011 The Author(s). Source

Huang S.,Institute for Systems Biology | Huang S.,University of Calgary
BioEssays | Year: 2013

The fateful combination of (i) the Dunning-Kruger effect (ignorance of one's own ignorance) with (ii) the nonlinear dynamics of the echo-chamber between reviewers and editors fuels a self-reinforcing collective delusion system that sometimes spirals uncontrollably away from objectivity and truth. Escape from this subconscious meta-ignorance is a formidable challenge but if achieved will help correct a central deficit of the peer-review process that stifles innovation and paradigm shifts. © 2013 WILEY Periodicals, Inc. Source

Liao W.,University of Calgary
International Journal of Computational Methods in Engineering Science and Mechanics | Year: 2012

In this paper, a fourth-order compact finite difference method is proposed to solve the unsteady convection-diffusion equation. We first transform the convection-diffusion equation to a reaction-diffusion equation, which is then solved by a compact high-order method. The new method is unconditionally stable and fourth-order accurate in both temporal and spatial dimensions. It requires only a three-point stencil for a one-dimensional problem and a five-point stencil for a two-dimensional problem. Two numerical examples are presented to demonstrate the efficiency and accuracy of the numerical method. Copyright © Taylor & Francis Group, LLC. Source

Theodor J.M.,University of Calgary
Journal of Vertebrate Paleontology | Year: 2010

Most recent phylogenetic analyses place the Cainotheriidae within the Tylopoda, but doubts about this placement within Tylopoda have been persistent. The Cainotheriidae are well known from numerous specimens and their cranial anatomy is well documented from complete, partial and disarticulated cranial material. However, high-resolution computed tomographic (CT) scans can still provide additional data to resolve problems in the interpretation of the auditory region, and allow comparison with other tylopod and ruminant taxa. Cainotheriids share several features with various groups within the Tylopoda, including an enlarged mastoid fossa, an inflated auditory bulla filled with cancellous bone, the presence of a sinus venosus temporalis, and what has been interpreted as a large flange of the periotic enclosing the petrobasilar canal. The reconstruction of the petrobasilar canal has been difficult to interpret, as the published figures are unclear. A micro-CT scan of Cainotherium (YPM 25037) shows the morphology is more complex. The periotic shows a smaller flange that does not enclose the petrobasilar canal. The skull base shows different arrangement of bones from other artiodactyls, presumably as a result of the enlargement of the auditory bulla, which has also affected the course of the petrobasilar canal. The otic region of Cainotherium shows no resemblances to ruminants, and features of this region are consistent with the Cainotheriidae being either a sister taxon to Tylopoda + Ruminantia, or with inclusion in a tylopod grouping. © 2010 by the Society of Vertebrate Paleontology. Source

El-Isa Z.H.,University of Jordan | Eaton D.W.,University of Calgary
Tectonophysics | Year: 2014

Interpretation of the b-value of earthquake frequency-magnitude distributions has received considerable attention in recent decades. This paper provides a comprehensive review of previous investigations of spatial and temporal variations in b-value, including their classification and possible causes. Based on least-squares regression of seismicity data compiled from the NEIC, IRIS and ISC catalogs, we find an average value of 1.02 ± 0.03 for the whole Earth and its two hemispheres, consistent with the general view that in seismically active regions the long-term average value is close to unity. Nevertheless, wide-ranging b-variations (0.3 ≤ b≤ 2.5) have been reported in the literature. This variability has been interpreted to arise from one or more of the following factors: prevailing stress state, crustal heterogeneity, focal depth, pore pressure, geothermal gradient, tectonic setting, petrological/environmental/geophysical characteristics, clustering of events, incomplete catalog data, and/or method of calculation. Excluding the latter, all of these factors appear to be linked, directly or indirectly, with the effective state of stress. Although time-dependent changes in b-value are well documented, conflicting observations reveal either a precursory increase or decrease in b value before major earthquakes. Our compilation of published analyses suggests that statistically significant b-variations occur globally on various timescales, including annual, monthly and perhaps diurnal. Taken together, our review suggests that b-variations are most plausibly linked with changes in effective stress. © 2013 Elsevier B.V. Source

Rock M.,University of Calgary
Critical Public Health | Year: 2013

Dog walking enables physical activity and positive social interactions, but uncontrolled dogs as well as dog feces can foster conflict and deter physical activity, for both dog owners and nonowners. This case study shows that previously reported associations with dogs (both positive and negative) can be linked to the wording and the day-to-day implementation of, or incompliance with, local governments' bylaws on pets. In this example of posthumanist health promotion, the policy goal is to optimize the overall impact on well-being of pet animals. Analytically, the case study draws together insights from actor-network theory, Foucault's theory of governmentality, Bourdieu's theory of habitus, and anthrozoology (i.e. the study of human-animal interactions as well as related ideas and norms). Posthumanist health promotion is a theoretically informed approach that can assist in developing policy and implementation strategies, not only on pets but on a range of topics. © 2013 Copyright Taylor and Francis Group, LLC. Source

Burton J.M.,University of Calgary
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques | Year: 2011

The "chronic cerebrospinal venous insufficiency" or "CCSVI" hypothesis, namely that multiple sclerosis (MS) is caused by abnormalities in the azygous and internal jugular veins with subsequent alterations in venous hemodynamics in the central nervous system, has been a dominant topic in MS care in Canada over the past year. Although there is no methodologically rigorous evidence to support this hypothesis presently, a considerable number of MS patients have undergone endovascular CCSVI procedures. Such procedures include angioplasty or stent placement in jugular and azygous veins. The safety and efficacy of these procedures is unknown, but not without risk. Chart and patient review of five patients with confirmed MS followed in Calgary were undertaken after patients came to medical attention by referral or admission secondary to complications believed to be associated with CCSVI procedures. Complications upon investigation and review included internal jugular vein stent thrombosis, cerebral sinovenous thrombosis, stent migration, cranial nerve injury and injury associated with venous catheterization. As the debate about CCSVI and its relationship to MS continues, the complications and risks associated with venous stenting and angioplasty in jugular and azygous veins are becoming clearer. As increasing numbers of MS patients are seeking such procedures, these five cases represent the beginning of a wave of complications for which standardized care guidelines do not exist. Our experience and that of our colleagues will be used to develop guidelines and strategies to monitor and manage these patients as their numbers increase. Source

Taylor V.H.,McMaster University | Macqueen G.M.,University of Calgary
Journal of Obesity | Year: 2010

Objective. Two major causes of disability, major depression and obesity, share overlapping psychosocial and pathophysiological etiologies. Studies are now focused on biological mechanisms linking the two illnesses, and there is interest in the role that adipokines may have in mediating the association between obesity and depression. We reviewed the literature to look at what is currently known about this association, focusing on the adipokines leptin, adiponectin, and resistin. Methods. A MEDLINE search, citing articles from 1966 onward, supplemented by a review of bibliographies, was conducted to identify relevant studies. Results. This paper identified plausible pathways underlying a link between adipokines and depression. Only a few studies have yet been conducted specifically examining these biomarkers in patients with depression, but the results are intriguing. Conclusion. This paper is one of the first to examine the association between adipokines and depression. It provides an overview of the physiological role of adipokines and summarizes the data suggesting that they may be dysregulated in major depression. This area of research may become increasingly important as new treatment strategies are developed. © 2010 Valerie H. Taylor and Glenda M. MacQueen. Source

Anisimov P.M.,Louisiana State University | Dowling J.P.,Louisiana State University | Sanders B.C.,University of Calgary
Physical Review Letters | Year: 2011

Autler-Townes splitting (ATS) and electromagnetically induced transparency (EIT) both yield transparency in an absorption profile, but only EIT yields strong transparency for a weak pump field due to Fano interference. Empirically discriminating EIT from ATS is important but so far has been subjective. We introduce an objective method, based on Akaike's information criterion, to test ATS vs EIT from experimental data for three-level atomic systems and determine which pertains. We apply our method to a recently reported induced-transparency experiment in superconducting-circuit quantum electrodynamics. © 2011 American Physical Society. Source

Rogers S.M.,University of Calgary
Current Biology | Year: 2015

The interplay between selection and genetic exchange at a color locus between populations of Timema walking sticks acts as an anti-speciation phenotype. This actively counteracts speciation and offers a general mechanism to explain the porous nature of species boundaries. © 2015 Elsevier Ltd All rights reserved. Source

Bharmal A.,University of Calgary
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques | Year: 2010

OBJECTIVE: To determine the outcomes of patients with Parkinson disease (PD) with pathological gambling (PG) from one Canadian Movement Disorders Clinic. METHODS: Assessments were performed in-person during routine clinic visits of all patients currently followed by one neurologist (OS). Pathological gambling was defined according to DSM-IV-TR criteria. Chart review was performed to obtain details on medication use, dosages, and patient demographics. Follow-up of patients with PG collected information on gambling behavior, PG management interventions, medications, treatment, and psychosocial outcomes. RESULTS: 146 patients were surveyed with an overall prevalence of PG of 4.1% (6/146). The rate of pathological gambling for those patients on dopamine agonist therapy (DA) was 8.1% (6/74). Only patients who were recreational gamblers prior to starting DA developed PG. All PG patients discontinued, decreased, or switched to another DA, and experienced a partial or full remission of PG. 3 (50%) patients described financial losses of $100,000 or more, and 75% (3/4) patients described significant marital stresses. At follow-up (August 2008), 4 of the 6 patients with PG continued to gamble in a controlled fashion despite medication changes. No significant difference in levodopa equivalent daily dose (LEDD) pre- and post-PG were observed; however, the relative amount of DA was decreased (p= 0.0593), while levodopa was relatively increased (p= 0.5277). Despite control of PG, patients still experience financial and marital strains. CONCLUSIONS: DA (in combination with levodopa) was associated with a significantly higher prevalence of PG in PD, particularly in patients who were recreational gamblers previously. Despite control of PG, patients continued to experience significant financial and marital stresses that should be regularly enquired upon in follow-up care and managed appropriately. Source

Wee Yong V.,University of Calgary
Neuroscientist | Year: 2010

Inflammation of the central nervous system (CNS) (neuroinflammation) is now recognized to be a feature of all neurological disorders. In multiple sclerosis, there is prominent infiltration of various leukocyte subsets into the CNS. Even when there is no significant inflammatory infiltrates, such as in Parkinson or Alzheimer disease, there is intense activation of microglia with resultant elevation of many inflammatory mediators within the CNS. An extensive dataset describes neuroinflammation to have detrimental consequences, but results emerging largely over the past decade have indicated that aspects of the inflammatory response are beneficial for CNS outcomes. Benefits of neuroinflammation now include neuroprotection, the mobilization of neural precursors for repair, remyelination, and even axonal regeneration. The findings that neuroinflammation can be beneficial should not be surprising as a properly directed inflammatory response in other tissues is a natural healing process after an insult. In this article, we review the data that highlight the dual aspects of neuroinflammation in being a hindrance on the one hand but also a significant help for recovery of the CNS on the other. We consider how the inflammatory response may be beneficial or injurious, and we describe strategies to harness the beneficial aspects of neuroinflammation. © The Author(s) 2010. Source

Ischemic heart disease is uncommon during pregnancy, occurring in approximately one in 10,000 live births. With the increasing age and fertility of mothers, the incidence of coronary artery disease in pregnancy is likely to increase. Atherosclerosis appears to be the most common cause of acute myocardial infarction, although coronary spasm, coronary dissection and thrombus have been reported, among others. The diagnosis of ischemic heart disease in the pregnant population can be challenging and not without risk to the fetus. Although there have been many reports of acute myocardial infarction and cardiopulmonary bypass surgery during pregnancy, most knowledge is based on anecdotal reports. Even less is known about the use of thrombolytics, percutaneous coronary intervention and the optimal medical management of ischemic heart disease during pregnancy. The epidemiology, diagnosis, medical and surgical treatment, and prognosis of ischemic heart disease in pregnancy are the subject of the present review. ©2010 Pulsus Group Inc. All rights reserved. Source

Vouloumanos A.,New York University | Curtin S.,University of Calgary
Cognitive Science | Year: 2014

Orienting biases for speech may provide a foundation for language development. Although human infants show a bias for listening to speech from birth, the relation of a speech bias to later language development has not been established. Here, we examine whether infants' attention to speech directly predicts expressive vocabulary. Infants listened to speech or non-speech in a preferential listening procedure. Results show that infants' attention to speech at 12 months significantly predicted expressive vocabulary at 18 months, while indices of general development did not. No predictive relationships were found for infants' attention to non-speech, or overall attention to sounds, suggesting that the relationship between speech and expressive vocabulary was not a function of infants' general attentiveness. Potentially ancient evolutionary perceptual capacities such as biases for conspecific vocalizations may provide a foundation for proficiency in formal systems such language, much like the approximate number sense may provide a foundation for formal mathematics. © 2014 Cognitive Science Society, Inc. Source

Zhong C.,Shanghai JiaoTong University | Hu W.B.,Shanghai JiaoTong University | Cheng Y.F.,University of Calgary
Journal of Materials Chemistry A | Year: 2013

The electro-oxidation of ammonia has attracted much attention in recent years since it addresses both the clean energy supply free of COx and environmental protection. However, the large-scale applications of ammonia electro-oxidation technologies have been strongly hindered by the insufficient performance and the high cost of the electrocatalysts related to the usage of high Pt loadings. Therefore, considerable effort has been devoted to developing electrocatalysts for ammonia electro-oxidation with improved activity and lower Pt loading over the past 10 years. From the initial focus on pure metal electrocatalysts, a wide range of Pt-based and Pt-free electrocatalysts for ammonia electro-oxidation have been investigated. This review begins with a brief discussion on the mechanism of the ammonia electro-oxidation with particular attention on the latest findings on the active intermediates and poisoning species, which is important for the fundamental understanding of the principles of improving the electrocatalyst performance for ammonia electro-oxidation. Typical types of electrocatalysts for ammonia electro-oxidation are next described, including pure metal, Pt alloy and Pt-free electrocatalysts. The various preparation methods are discussed and related to the resulting structures and electrocatalytic properties for ammonia electro-oxidation. The factors influencing the performance of the electrocatalysts are also highlighted for gaining fundamental insight into the optimization of the electrocatalyst performance. Based on the results achieved in this area, several future research directions are finally proposed and discussed. © 2013 The Royal Society of Chemistry. Source

The invasive nature of glioblastoma renders them incurable by current therapeutic interventions. Using a novel invasive human glioma model, we previously identified the neurotrophin receptor p75NTR (aka CD271) as a mediator of glioma invasion. Herein, we provide evidence that preventing phosphorylation of p75NTR on S303 by pharmacological inhibition of PKA, or by a mutational strategy (S303G), cripples p75NTR-mediated glioma invasion resulting in serine phosphorylation within the C-terminal PDZ-binding motif (SPV) of p75NTR. Consistent with this, deletion (ΔSPV) or mutation (SPM) of the PDZ motif results in abrogation of p75NTR-mediated invasion. Using a peptide-based strategy, we identified PDLIM1 as a novel signaling adaptor for p75NTR and provide the first evidence for a regulated interaction via S425 phosphorylation. Importantly, PDLIM1 was shown to interact with p75NTR in highly invasive patient-derived glioma stem cells/tumor-initiating cells and shRNA knockdown of PDLIM1 in vitro and in vivo results in complete ablation of p75NTR-mediated invasion. Collectively, these data demonstrate a requirement for a regulated interaction of p75NTR with PDLIM1 and suggest that targeting either the PDZ domain interactions and/or the phosphorylation of p75NTR by PKA could provide therapeutic strategies for patients with glioblastoma.Oncogene advance online publication, 29 June 2015; doi:10.1038/onc.2015.199. © 2015 Macmillan Publishers Limited Source

Swain M.G.,University of Calgary
Digestive Diseases | Year: 2010

Natural killer T (NKT) cells are distinct innate immune T cells which play a key role in the pathogenesis of various immune-mediated liver diseases. NKT cells are traditionally defined as cells that co-express the T cell receptor (TCR) and certain natural killer cell surface markers (e.g. NK1.1 in some mouse strains). Based on CD1d restriction, they are broadly classified as invariant (iNKT) and noninvariant NKT cells. Both NKT cell types are abundant within the liver and, mainly through the study of animal models of immune-mediated liver injury, the role of NKT cells in the context of liver inflammation is becoming better understood. iNKT cells are the NKT cell subtype which has been most well characterized, and therefore this paper will focus mainly on iNKT cells. NKT cells recognize both host and microbial glycolipid antigens, presented by antigen-presenting cells in the context of the MHC class I- like molecule CD1d, via their T cell receptor. Upon activation, NKT cells rapidly release large quantities of T helper type 1 (Th1; e.g. IFN-γ, TNF-α), Th2 (e.g. IL-4, IL-10), and Th17 (e.g. IL-17, IL-22) type cytokines, with diverse immunoregulatory and immunomodulatory effects. Moreover, through the release of these cytokines, NKT cells can drive subsequent downstream immune responses in tissues such as the liver, including the upregulation of adhesion molecule expression and increased chemokine production. By regulating immune cell adhesion pathways and chemokine secretion, NKT cells can direct both pro-inflammatory (e.g. Th1 cell) and anti-inflammatory (e.g. regulatory T cell) cell infiltration into the liver. Through this mechanism, NKT cells orchestrate a balance between pro- and anti-inflammatory responses within the liver during immune-mediated liver damage. This paper highlights the diverse roles played by iNKT cells as master regulators of immune-mediated liver injury. Copyright © 2010 S. Karger AG, Basel. Source

Lang M.J.,University of Calgary
Acta neurochirurgica. Supplement | Year: 2011

This manuscript describes the development and ongoing integration of neuroArm, an image-guided MR-compatible robot. A neurosurgical robotics platform was developed, including MR-compatible manipulators, or arms, with seven degrees of freedom, a main system controller, and a human-machine interface. This system was evaluated during pre-clinical trials and subsequent clinical application, combined with intra-operative MRI, at both 1.5 and 3.0 T. An MR-compatible surgical robot was successfully developed and merged with ioMRI at both 1.5 or 3.0 T. Image-guidance accuracy and microsurgical capability were established in pre-clinical trials. Early clinical experience demonstrated feasibility and showed the importance of a master-slave configuration. Surgeon-directed manipulator control improved performance and safety. NeuroArm successfully united the precision and accuracy of robotics with the executive decision-making capability of the surgeon. Source

Purposes: To assess the accuracy of estimates using statistical databases of influenza-associated morbidity and mortality, and precisely measure influenza vaccine effectiveness. Principal results: Laboratory testing of influenza is incomplete. Death certificates under-report influenza. Statistical database models are used as an alternative to randomised controlled trials (RCTs) to assess influenza vaccine effectiveness. Evidence of the accuracy of influenza morbidity and mortality estimates was sought from: (1) Studies comparing statistical models. For four studies Poisson and ARIMA models produced higher estimates than Serfling, and Serfling higher than GLM. Which model is more accurate is unknown. (2) Studies controlling confounders. Fourteen studies mostly controlled one confounder (one controlled comorbidities), and limited control of confounders limits accuracy. Evidence for vaccine effectiveness was sought from: (1) Studies of regions with increasing vaccination rates. Of five studies two controlled for confounders and one found a positive vaccination effect. Three studies did not control confounders and two found no effect of vaccination. (2) Studies controlling multiple confounders. Of thirteen studies only two found a positive vaccine effect and no mortality differences between vaccinees and non-vaccinees in non-influenza seasons, showing confounders were controlled. Key problems are insufficient testing for influenza, using influenza-like illness, heterogeneity of seasonal and pandemic influenza, population aging, and incomplete confounder control (co-morbidities, frailty, vaccination history) and failure to demonstrate control of confounders by proving no mortality differences between vaccinees and non-vaccinees in non-influenza seasons. Major conclusions: Improving model accuracy requires proof of no mortality differences in pre-influenza periods between the vaccinated and non-vaccinated groups, and reduction in influenza morbidity and mortality in seasons with a good vaccine match, more virulent strains, in the younger elderly with less immune senescence, and specific outcomes (laboratory-confirmed outcomes, pneumonia deaths).Proving influenza vaccine effectiveness requires appropriately powered RCTs, testing participants with RT-PCR tests, and comprehensively monitoring morbidity and mortality. © 2014 Elsevier Ltd. Source

Hamilton A.,University of Western Ontario | Zamponi G.W.,University of Calgary | Ferguson S.S.G.,University of Western Ontario
Molecular Brain | Year: 2015

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that affects 36 million people worldwide, but currently has no effective treatment options. One of the original hallmarks of AD are plaques comprised of beta amyloid (Aβ) and neurofibrillary tangles comprised of phosphorylated Tau protein. However, it is soluble oligomeric Aβ which is more closely correlated with cognitive decline and is therefore considered to be the neurotoxic species. Oligomeric Aβ has recently been shown to form complexes with the glycosylphosphatidylinositol (GPI)-anchored membrane protein, cellular prion protein (PrPc), and these complexes are believed to play an important role in the progression of AD pathogenesis. Glutamate, the major excitatory neurotransmitter is responsible for mediating learning and memory under normal physiological conditions. However, the dysregulation of glutamatergic signaling has also been implicated in a number of neurodegenerative diseases including AD. Glutamate acts via both ionotropic glutamate receptors (iGluR) and metabotropic glutamate receptors (mGluR), each of which have been implicated in AD. There is now growing evidence to suggest that mGluR5 may contribute the AD pathogenesis by acting as scaffolds for the PrPc/Aβ oligomer complex, enabling the propagation of neurotoxic signaling in AD. In addition, PrPc and Aβ oligomer signaling via NMDARs may also contribute to AD pathology. The current review overviews our current understanding of the role of PrPc and Aβ oligomers in regulating glutamate receptor signaling, as well as highlights the importance of understanding these signaling complexes to develop more effective therapeutic strategies to treat AD. © 2015 Hamilton et al.; licensee BioMed Central. Source

Thomas R.E.,University of Calgary
The Cochrane database of systematic reviews | Year: 2013

Healthcare workers' influenza rates are unknown but may be similar to those of the general public. Healthcare workers may transmit influenza to patients. To identify all randomised controlled trials (RCTs) and non-RCTs assessing the effects of vaccinating healthcare workers on the incidence of laboratory-proven influenza, pneumonia, death from pneumonia and admission to hospital for respiratory illness in those aged 60 years or older resident in long-term care institutions (LTCIs). We searched CENTRAL 2013, Issue 2, MEDLINE (1966 to March week 3, 2013), EMBASE (1974 to March 2013), Biological Abstracts (1969 to March 2013), Science Citation Index-Expanded (1974 to March 2013) and Web of Science (2006 to March 2013). Randomised controlled trials (RCTs) and non-RCTs of influenza vaccination of healthcare workers caring for individuals aged 60 years or older in LTCIs and the incidence of laboratory-proven influenza and its complications (lower respiratory tract infection, or hospitalisation or death due to lower respiratory tract infection) in individuals aged 60 years or older in LTCIs. Two authors independently extracted data and assessed risk of bias. We identified four cluster-RCTs (C-RCTs) (n = 7558) and one cohort study (n = 12,742) of influenza vaccination for HCWs caring for individuals ≥ 60 years in LTCFs. Three RCTs (5896 participants) provided outcome data that met our criteria. These three studies were comparable in study populations, intervention and outcome measures. The studies did not report adverse events. The principal sources of bias in the studies related to attrition and blinding. The pooled risk difference (RD) from the three cluster-RCTs for laboratory-proven influenza was 0 (95% confidence interval (CI) -0.03 to 0.03) and for hospitalisation was RD 0 (95% CI -0.02 to 0.02). The estimated risk of death due to lower respiratory tract infection was also imprecise (RD -0.02, 95% CI -0.06 to 0.02) in individuals aged 60 years or older in LTCIs. Adjusted analyses which took into account the cluster design did not differ substantively from the pooled analysis with unadjusted data. The results for specific outcomes: laboratory-proven influenza or its complications (lower respiratory tract infection, or hospitalisation or death due to lower respiratory tract illness) did not identify a benefit of healthcare worker vaccination on these key outcomes. This review did not find information on co-interventions with healthcare worker vaccination: hand-washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding admissions, antivirals and asking healthcare workers with influenza or influenza-like-illness (ILI) not to work. This review does not provide reasonable evidence to support the vaccination of healthcare workers to prevent influenza in those aged 60 years or older resident in LTCIs. High-quality RCTs are required to avoid the risks of bias in methodology and conduct identified by this review and to test further these interventions in combination. Source

Genuis S.J.,University of Calgary | Kelln K.L.,University of Saskatchewan
Behavioural Neurology | Year: 2015

Juxtaposed alongside the ongoing rise in the incidence and prevalence of dementia, is the surge of recent research confirming widespread exposure and bioaccumulation of chemical toxicants. Evidence from sources such as the Centers for Disease Control reveals that most people have accrued varying degrees of assorted toxic pollutants including heavy metals, flame retardants, and pesticide residues within their bodies. It has been well established that many of these toxicants have neurodegenerative as well as neurodevelopmental impact as a result of various pathophysiologic mechanisms including neuronal mitochondrial toxicity and disruption of neurotransmitter regulation. Elimination of stockpiled toxicants from the body may diminish adverse toxicant impact on human biology and allow restoration of normal physiological function. Incorporating a review of medical literature on toxicant exposure and dementia with a case history of a lead-exposed individual diagnosed with dementia, this paper will discuss a much overlooked and potentially widespread cause of declining brain function and dementia. © 2015 Stephen J. Genuis and Kasie L. Kelln. Source

Mohtadi N.G.,University of Calgary
Cochrane database of systematic reviews (Online) | Year: 2011

Reconstruction of the anterior cruciate ligament (ACL) commonly involves patellar tendon (PT) or hamstring tendon(s) (HT) autografts. There is no consensus with respect to the choice between these two grafts in ACL surgery. This review compared the outcomes of ACL reconstruction using PT versus HT autografts in ACL deficient patients. We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (April 2008), the Cochrane Central Register of Controlled Trials (2008, Issue 2), MEDLINE (1966 to April 10 2008), EMBASE (1980 to April 10 2008), conference proceedings and reference lists. No language restrictions were applied. Randomized and quasi-randomized controlled trials comparing outcomes (minimum two year follow-up) following ACL reconstruction using either PT or HT autografts in skeletally mature adults, irrespective of the number of bundles, fixation method or incision technique. After independent study selection, the four authors independently assessed trial quality and risk of bias, and extracted data using pre-developed forms. Trial authors were contacted for additional data and information. Risk ratios with 95% confidence intervals were calculated for dichotomous outcomes, and mean differences and 95% confidence intervals for continuous outcomes. Nineteen trials providing outcome data for 1597 young to middle-aged adults were included. Many trials were at high risk of bias reflecting inadequate methods of randomization, lack of blinding and incomplete assessment of outcome.Pooled data for primary outcomes, reported in a minority of trials, showed no statistically significant differences between the two graft choices for functional assessment (single leg hop test), return to activity, Tegner and Lysholm scores, and subjective measures of outcome. There were also no differences found between the two interventions for re-rupture or International Knee Documentation Committee scores. There were inadequate long-term results, such as to assess the development of osteoarthritis.All tests (instrumental, Lachman, pivot shift) for static stability consistently showed that PT reconstruction resulted in a more statically stable knee compared with HT reconstruction. Conversely, patients experienced more anterior knee problems, especially with kneeling, after PT reconstruction. PT reconstructions resulted in a statistically significant loss of extension range of motion and a trend towards loss of knee extension strength. HT reconstructions demonstrated a trend towards loss of flexion range of motion and a statistically significant loss of knee flexion strength. The clinical importance of the above range of motion losses is unclear. There is insufficient evidence to draw conclusions on differences between the two grafts for long-term functional outcome. While PT reconstructions are more likely to result in statically stable knees, they are also associated with more anterior knee problems. Source

Gour G.,University of Calgary | Gour G.,University of California at San Diego | Wallach N.R.,University of California at San Diego
Physical Review Letters | Year: 2013

We provide a systematic classification of multiparticle entanglement in terms of equivalence classes of states under stochastic local operations and classical communication (SLOCC). We show that such a SLOCC equivalency class of states is characterized by ratios of homogenous polynomials that are invariant under local action of the special linear group. We then construct the complete set of all such SL-invariant polynomials (SLIPs). Our construction is based on Schur-Weyl duality and applies to any number of qudits in all (finite) dimensions. In addition, we provide an elegant formula for the dimension of the homogenous SLIPs space of a fixed degree as a function of the number of qudits. The expressions for the SLIPs involve in general many terms, but for the case of qubits we also provide much simpler expressions. © 2013 American Physical Society. Source

Darbyshire F.A.,University of Quebec at Montreal | Eaton D.W.,University of Calgary
Lithos | Year: 2010

We characterise the nature and thickness of the seismological lithosphere beneath Hudson Bay, using dispersion analysis of fundamental-mode Rayleigh waves along two-station paths crossing the region. Hudson Bay is largely underlain by the Paleoproterozoic Trans-Hudson Orogen, and is surrounded by Archean cratons. This study region thus provides an opportunity to investigate whether fundamental differences exist in the nature of the subcontinental lithosphere between Archean and Proterozoic terranes.Dispersion measurements for Hudson Bay, carried out in the ~15-220. s period range, show seismic phase velocities consistently higher than those derived from global reference models. In addition, the phase velocities are higher than those of the Canadian Shield average, and of many other cratonic regions worldwide. Monte-Carlo modelling is used to estimate 1D shear wave velocity profiles for each of the dispersion curves. The models are characterised by a high-velocity 'lid', interpreted as the seismological expression of the subcontinental lithosphere, beneath which velocities decrease gradually toward global reference values. We find lithospheric thicknesses in the range 185-260. km beneath the Hudson Bay region, with maximum lithospheric shear wave velocity perturbations of 4.5-7.3% above global reference values.By treating the geotherm as a free parameter, the average dispersion curve for Hudson Bay can be fit using laboratory based mineral-physics relations with simple compositional models, including constant-composition and layered-mantle models. Low mantle temperatures, corresponding to surface heat-flow values between 37 and 40mW/m2, are required to match the observed data. A layered model based on the Archean Slave craton is favoured as it provides a lithospheric root that is close to the isopycnic state (i.e., neutrally buoyant for all depths).In common with studies of other continental shields (particularly Fennoscandia and central Australia), the velocity structure modelled for the Hudson Bay region suggests that there is no systematic difference between the velocity structure and thickness of Archean and Proterozoic seismological lithosphere. This result may have important implications for models of lithospheric stabilisation and evolution between 2.8 and 1.8. Ga. © 2010 Elsevier B.V. Source

Federico S.,University of Calgary | Gasser T.C.,KTH Royal Institute of Technology
Journal of the Royal Society Interface | Year: 2010

The elastic strain energy potential for nonlinear fibre-reinforced materials is customarily obtained by superposition of the potentials of the matrix and of each family of fibres. Composites with statistically oriented fibres, such as biological tissues, can be seen as being reinforced by a continuous infinity of fibre families, the orientation of which can be represented by means of a probability density function defined on the unit sphere (i.e. the solid angle). In this case, the superposition procedure gives rise to an integral form of the elastic potential such that the deformation features in the integral, which therefore cannot be calculated a priori. As a consequence, an analytical use of this potential is impossible. In this paper, we implemented this integral form of the elastic potential into a numerical procedure that evaluates the potential, the stress and the elasticity tensor at each deformation step. The numerical integration over the unit sphere is performed by means of the method of spherical designs, in which the result of the integral is approximated by a suitable sum over a discrete subset of the unit sphere. As an example of application, we modelled the collagen fibre distribution in articular cartilage, and used it in simulating displacement-controlled tests: the unconfined compression of a cylindrical sample and the contact problem in the hip joint. © 2010 The Royal Society. Source

Rucklidge J.J.,University of Canterbury | Kaplan B.J.,University of Calgary
Expert Review of Neurotherapeutics | Year: 2013

Ingesting minerals and vitamins in combination makes physiological sense, and research on the use of broad-spectrum formulations for psychiatric symptoms is increasing rapidly. This review covers formulas consisting of at least four vitamins and/or minerals and includes four experimental designs: randomized controlled trials, open-label trials, case-control studies and case studies with within-subject crossovers. Nevertheless, there is evidence for the efficacy of micronutrients in the treatment of stress and antisocial behaviors as well as depressed mood in nonclinical and elderly populations. Many reports studied mood changes in healthy populations, making it difficult to generalize to clinical samples. There is also preliminary support for the treatment of autism with micronutrients. However, despite positive preliminary findings, there are less data available to support efficacy of micronutrient formulas in treating bipolar disorder, attention deficit-hyperactivity disorder and substance abuse/dependence and no clinical trials have been done with clinically depressed or anxious patient samples, psychosis or eating disorders. © 2013 2013 Expert Reviews Ltd. Source

Kurepin L.V.,University of Western Ontario | Pharis R.P.,University of Calgary
Plant Science | Year: 2014

Shoot growth of dicot plants is rigorously controlled by the interactions of environmental cues with several groups of phytohormones. The signaling effects of light on shoot growth are of special interest, as both light irradiance and light quality change rapidly throughout the day, causing profound changes in stem elongation and leaf area growth. Among the several dicot species examined, we have focused on sunflower ( Helianthus annuus L.) because its shoots are robust and their growth is highly plastic. Sunflower shoots thus constitute an ideal tissue for assessing responses to both light irradiance and light quality signals. Herein, we discuss the possible roles of gibberellins, auxin, ethylene, cytokinins and brassinosteroids in mediating the stem elongation and leaf area growth that is induced by shade light. To do this we uncoupled the plant's responses to changes in the red to far-red [R/FR] light ratio from its responses to changes in irradiance of photosynthetically active radiation [PAR]. Reducing each of R/FR light ratio and PAR irradiance results in increased sunflower stem elongation. However, the plant's response for leaf area growth differs considerably, with a low R/FR ratio generally promoting leaf area growth, whereas low irradiance PAR inhibits it. The increased stem elongation that occurs in response to lowering R/FR ratio and PAR irradiance is accomplished at the expense of leaf area growth. In effect, the low PAR irradiance signal overrides the low R/FR ratio signal in shade light's control of leaf growth and development. Three hormone groups, gibberellins, auxin and ethylene are directly involved in regulating these light-mediated shoot growth changes. Gibberellins and auxin function as growth promoters, with auxin likely acting as an up-regulator of gibberellin biosynthesis. Ethylene functions as a growth-inhibitor and probably interacts with gibberellins in regulating both stem and leaf growth of the sunflower shoot. © 2014. Source

Lazo-Langner A.,University of Western Ontario | Lang E.S.,University of Calgary | Douketis J.,McMaster University
Critical Care | Year: 2013

New oral anticoagulants, including dabigatran, rivaroxaban, and apixaban, have been recently approved for primary and secondary prophylaxis of thromboembolic conditions. However, there is no clear strategy for managing and reversing their anticoagulant effects. We aimed to summarize the available evidence for clinical management and reversal of bleeding associated with new oral anticoagulants. Using a systematic review approach, we aimed to identify studies describing reversal strategies for dabigatran, rivaroxaban, and apixaban. The search was conducted using Medline, EMBASE, HealthSTAR, and grey literature. We included laboratory and human studies. We included 23 studies reported in 37 out of 106 potentially relevant references. Four studies were conducted in humans and the rest were in vitro and in vivo studies. The majority of the studies evaluated the use of prothrombinase complex concentrate (PCC), either activated or inactivated, and recombinant activated factor VII (rFVIIa). Other interventions were also identified. Laboratory studies suggest that hemostatic parameters and bleeding might be partially or completely corrected by PCC for rivaroxaban better than dabigatran. Studies in humans suggest that PCC might reverse the effects of rivaroxaban better than dabigatran assessed by hemostatic tests. We were not able to locate studies evaluating the clinical efficacy of these agents. The best available evidence suggests that PCC (activated or inactivated) might be the best option for reversing new anticoagulants. Evidence for rFVIIa is less compelling. There might be differences in the efficacy of reversing agents for different anticoagulants. Studies assessing the clinical efficacy of these reversal agents are urgently needed. © 2013 BioMed Central Ltd. Source

Piers W.E.,University of Calgary
Organometallics | Year: 2011

Advances in the field of organometallic chemistry have historically been driven by the imperatives of the petrochemical industry. Catalytic manipulation of C-H and C-C bonds is now at an advanced stage of sophistication, although significant opportunities continue to exist in this aspect of organometallic chemistry. However, application of the formidable toolbox of organometallic chemistry-developed in the context of hydrocarbon chemistry-to the sustainable production of environmentally benign solar fuels is a research problem that humanity needs organometallic chemists to tackle. Organometallic approaches to water splitting driven by sunlight will constitute a growing area of focus in the coming years. © 2011 American Chemical Society. Source

Ball C.G.,University of Calgary
Current Opinion in Critical Care | Year: 2015

Purpose of review Damage control surgery (DCS) has become a lifesaving maneuver for critically injured patients when utilized in appropriate scenarios. Despite this reality, indications for initiating DCS remain debated. Recent findings Despite discussion surrounding the appropriate indications for DCS, this series of fundamental principles includes a rapidly abbreviated operative intervention aimed at arresting ongoing hemorrhage and containing gastrointestinal contamination in a patient approaching physiologic exhaustion, which includes both vascular and nonvascular damage control techniques, in addition to management of the open abdomen. Patients are then returned to the operating theater for definitive reconstruction once their physiology has been stabilized within the ICU. Summary DCS is lifesaving when applied in appropriate clinical scenarios involving critically injured patients. Overuse of this technique can lead to increased patient morbidity and cost however. © 2015 Wolters Kluwer Health, Inc. All rights reserved. Source

Wang Y.,University of Calgary
International Journal of Cognitive Informatics and Natural Intelligence | Year: 2012

A key notion in abstract intelligence and cognitive informatics is that the brain and natural intelligence may only be explained by a hierarchical and reductive theory that maps the brain through the embodied neurological, physiological, cognitive, and logical levels from bottom-up induction and top-down deduction. This paper presents an abstract intelligence framework for modeling the structures and functions of the brain across these four levels. A set of abstract intelligent model, cognitive functional model, and neurophysiological model of the brain is systematically developed. On the basis of the abstract intelligent models of the brain at different levels, the conventionally highly overlapped, redundant, and even contradicted empirical observations in brain studies and cognitive psychology may be rigorously clarified and neatly explained. The improved understanding about the brain has led to the development of a wide range of novel technologies and systems such as cognitive computers, cognitive robots, and other applied cognitive systems. Copyright © 2012, IGI Global. Source

Fortescue B.,Southern Illinois University Carbondale | Gour G.,University of Calgary
IEEE Transactions on Information Theory | Year: 2012

We demonstrate a new construction for perfect quantum secret sharing (QSS) schemes based on imperfect ramp secret sharing combined with classical encryption, in which the individual parties' shares are split into quantum and classical components, allowing the former to be of lower dimension than the secret itself. We show that such schemes can be performed with smaller quantum components and lower overall quantum communication than required for existing methods. We further demonstrate that one may combine both imperfect quantum and imperfect classical secret sharing to produce an overall perfect QSS scheme, and that examples of such schemes (which we construct) can have the smallest quantum and classical share components possible for their access structures, something provably not achievable using perfect underlying schemes. Our construction has significant potential for being adapted to other QSS schemes based on stabilizer codes. © 1963-2012 IEEE. Source

Patten S.B.,University of Calgary
Epidemiology and Psychiatric Sciences | Year: 2015

The heterogeneity of clinical syndromes subsumed by diagnostic criteria for major depressive disorder (MDD) is regarded by some as a reason to abandon or modify the criteria. However, heterogeneity may be unavoidable because of the biopsychosocial complexity of depression. MDD may be characterised by complexities that cannot be distilled down to any brief set of diagnostic criteria. Psychiatrists and psychiatric epidemiologists may need to revise their expectations of this diagnosis in order to avoid over-estimating its ability to guide the selection of treatments and prediction of prognosis. An opposing perspective is that of reification, in which the diagnosis is viewed as being more real than it really is. The concept of rheostasis may help to explain some features of this condition, such as why major depressive episodes sometimes seem understandable or even adaptive (e.g. in the context of bereavement) whereas at other times such episodes are inexplicable and maladaptive. © 2015 Cambridge University Press. Source

Glannon W.,University of Calgary
The Journal of clinical ethics | Year: 2010

Deep brain stimulation (DBS) of the globus pallidus interna and subthalamic nucleus has restored some degree of motor control in many patients in advanced stages of Parkinson's disease. DBS has also been used to treat dystonia, essential tremor (progressive neurological condition causing trembling), chronic pain, obsessive-compulsive disorder, Tourette's syndrome, major depressive disorder, obesity, cerebral palsy, and the minimally conscious state. Although the underlying mechanisms of the technique are still not clear, DBS can modulate underactive or overactive neural circuits and restore disrupted communication between and among groups of neurons in interacting regions of the brain.This can control and relieve many symptoms associated with a range of neurological and psychiatric disorders. But the procedures of implanting and stimulating the electrodes are brain-invasive and entail significant risks. Some patients receiving DBS have experienced intracerebral hemorrhage, infection, cognitive disturbances such as impulsive behavior, and affective disturbances such as mania. It is not known whether continuous electrical stimulation of the brain would reshape synaptic connectivity and permanently alter neural circuits in ways that may not be salutary. The risk of these effects indicates that DBS should be used only when a patient's condition is refractory to all other interventions and when there is a high probability that the technique will benefit the patient and improve his or her quality of life. If a patient's quality of life is poor and all other treatment options have been exhausted, then the likelihood of benefit can justify physicians' exposing patients to some risk. The clinical and ethical significance of the risk in DBS underscores the obligation of physicians to obtain fully informed consent from patients undergoing the procedure. Source

Tonelli M.,University of Alberta | Pannu N.,University of Alberta | Manns B.,University of Calgary
New England Journal of Medicine | Year: 2010

Hyperphosphatemia, which is nearly universal in kidney failure, is accompanied by low serum levels of vitamin D and hypocalcemia. Without treatment, severe secondary hyperparathyroidism occurs, which may result in painful fractures, brown tumors, and generalized osteopenia. This article reviews the rationale for treatment with oral phosphate binders, discusses evidence supporting the use of available agents, and suggests an approach for clinical practice. Copyright © 2010 Massachusetts Medical Society. All rights reserved. Source

Becker W.J.,University of Calgary
Headache | Year: 2010

This review was developed as part of a debate, and takes the "pro" stance that abnormalities of structures in the neck can be a significant source of headache. The argument for this is developed from a review of the medical literature, and is made in 5 steps. It is clear that the cervical region contains many pain-sensitive structures, and that these are prone to injury. The anatomical and physiological mechanisms are in place to allow referral of pain to the head including frontal head regions and even the orbit in patients with pain originating from many of these neck structures. Clinical studies have shown that pain from cervical spine structures can in fact be referred to the head. Finally, clinical treatment trials involving patients with proven painful disorders of upper cervical zygapophysial joints have shown significant headache relief with treatment directed at cervical pain generators. In conclusion, painful disorders of the neck can give rise to headache, and the challenge is to identify these patients and treat them successfully. © 2010 American Headache Society. Source

Raedler T.J.,University of Calgary
Current Opinion in Psychiatry | Year: 2010

Purpose of Review: Schizophrenia is associated with increased mortality and reduced life expectancy, with cardiovascular disease being the most frequent cause of death. Antipsychotics have detrimental effects on different risk factors for cardiovascular disease. This review will focus on the relationship between antipsychotic treatment and cardiovascular disease. Recent Findings: The increased overall mortality and mortality from cardiovascular disease in schizophrenia are now well documented. Patients with schizophrenia are at risk of receiving less optimal treatment for cardiovascular disease. Patients with schizophrenia are at high risk of metabolic syndrome, a cluster of risk factors for cardiovascular disease. Some antipsychotics, in particular, clozapine and olanzapine, frequently cause weight gain, dyslipidemia and diabetes mellitus. Antipsychotics differ in their effects on body weight, lipids and glucose regulation. However, the long-term effects of these differences between individual antipsychotics on overall mortality and cardiovascular mortality are not well established. Summary: More research is needed to better understand the relationship between schizophrenia, antipsychotic treatment and cardiovascular disease. More effective treatment strategies need to be developed to reduce the burden of cardiovascular disease in schizophrenia. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Young N.M.,University of California at San Francisco | Wagner G.P.,Yale University | Hallgrimsson B.,University of Calgary
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

The long legs and short arms of humans are distinctive for a primate, the result of selection acting in opposite directions on each limb at different points in our evolutionary history. This mosaic pattern challenges our understanding of the relationship of development and evolvability because limbs are serially homologous and genetic correlations should act as a significant constraint on their independent evolution. Here we test a developmental model of limb covariation in anthropoid primates and demonstrate that both humans and apes exhibit significantly reduced integration between limbs when compared to quadrupedal monkeys. This result indicates that fossil hominins likely escaped constraints on independent limb variation via reductions to genetic pleiotropy in an ape-like last common ancestor (LCA). This critical change in integration among hominoids, which is reflected in macroevolutionary differences in the disparity between limb lengths, facilitated selection for modern human limb proportions and demonstrates how development helps shape evolutionary change. Source

Whelan P.J.,University of Calgary
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010

Rhythmic activity is responsible for numerous essential motor functions including locomotion, breathing and chewing. In the case of locomotion, it has been realized for some time that the spinal cord contains sufficient circuitry to produce a sophisticated stepping pattern. However, the central pattern generator for locomotion in mammals has remained a 'black box' where inputs to the network were manipulated and the outputs interpreted. Over the last decade, new genetic approaches and techniques have been developed that provide ways to identify and manipulate the activity of classes of interneurons. The use of these techniques will be critically discussed and related to current models of network function. © 2010 The Royal Society. Source

Ferguson G.,University of Saskatchewan | Jasechko S.,University of Calgary
Geophysical Research Letters | Year: 2015

Stable isotopes have been used to study large-scale changes in hydrology during the Pleistocene epoch. Many of these efforts have required an estimate of the δ18O value of runoff generated by melting ice sheets. There is no consensus on representative values. Here we examine δ18O values from fossil groundwater samples and isotope-enabled general circulation models (GCMs) to better understand the isotopic composition of the Laurentide Ice Sheet (LIS). Groundwater δ18O values ranged from -12.5 to -25.3‰ and tended to increase southward. The δ18O precipitation values predicted by GCMs follow a similar trend but increase more steeply southward. The difference in groundwater and GCM output can be explained by invoking movement of glacial ice and meltwater, along with mixing within groundwater systems. Most groundwater δ18O values are higher than an average LIS δ18O value of -25.4 ± 2.5‰ calculated based on estimated ice sheet volumes and sea level data. © 2015. American Geophysical Union. All Rights Reserved. Source

Stelfox H.T.,University of Calgary | Bagshaw S.M.,University of Alberta | Gao S.,Alberta Health Services
Critical Care Medicine | Year: 2014

OBJECTIVE:: To describe the occurrence of recurrent clinical deterioration and repeat medical emergency team activation and assess its effect on processes and outcomes of care. DESIGN:: Retrospective cohort study. SETTING:: Two community hospitals and two tertiary care hospitals, Alberta, Canada. PATIENTS:: Consecutive hospitalized adult patients with sudden clinical deterioration and medical emergency team activation without admission to ICU. INTERVENTION:: None. MEASUREMENT AND MAIN RESULTS:: We compared ICU admission rates (admissions > 2 hr following index medical emergency team), hospital length of stay, and hospital mortality for a cohort of 3,200 patients with and without recurrent clinical deterioration following medical emergency team activation adjusting for patient, provider, and hospital characteristics.The cohort consisted of 3,200 patients. Ten percent of patients (n = 337) experienced recurrent clinical deterioration and repeat medical emergency team activation during their hospital stay. Patients more likely to experience recurrent clinical deterioration and repeat medical emergency team activation included those with chronic liver disease (odds ratio, 1.75; 95% CI, 1.14-2.69) or who received airway suctioning (odds ratio, 1.66; 95% CI, 1.23-2.25), noninvasive mechanical ventilation (odds ratio, 1.67; 95% CI, 0.94-2.94), or central IV catheter insertion (odds ratio, 1.81; 95% CI, 1.02-3.21) during the index medical emergency team activation. Patients with recurrent clinical deterioration were more likely than patients without recurrent clinical deterioration to be subsequently admitted to ICU (43% vs 13%; odds ratio, 6.11; 95% CI, 4.67-8.00; p < 0.01), to have longer lengths of hospital stay (median, 31 d vs 13 d; p < 0.01), and to die during their hospital stay (34% vs 23%; odds ratio, 1.98; 95% CI, 1.47-2.67; p < 0.01). CONCLUSIONS:: Recurrent clinical deterioration and repeat medical emergency team activation are common and associated with increased risk of subsequent ICU admission, increased length of hospital stay, and increased hospital mortality. It may be possible to identify patients at risk of recurrent clinical deterioration following medical emergency team activation and target interventions to improve patient care. © 2014 by the Society of Critical Care Medicine. Source

Wilson J.R.,University of Calgary
Channels (Austin, Tex.) | Year: 2011

The resting membrane potential, E(m), of mammalian cells is a fundamental physiological parameter. Even small changes in E(m) can modulate excitability, contractility and rates of cell migration. At present accurate, reproducible measurements of E(m) and determination of its ionic basis remain significant challenges when patch clamp methods are applied to small cells. In this study, a mathematical model has been developed which incorporates many of the main biophysical principles which govern recordings of the resting potential of 'small cells'. Such a prototypical cell (approx. capacitance, 6 pF; input resistance 5 GΩ) is representative of neonatal cardiac myocytes, and other cells in the cardiovascular system (endothelium, fibroblasts) and small cells in other tissues, e.g. bone (osteoclasts) articular joints (chondrocytes) and the pancreas (β cells). Two common experimental conditions have been examined: (1) when the background K(+) conductance is linear; and (2) when this K(+) conductance is highly nonlinear and shows pronounced inward rectification. In the case of a linear K(+) conductance, the presence of a "leakage" current through the seal resistance between the cell membrane and the patch pipette always depolarizes E(m). Our calculations confirm that accurate characterization of E(m) is possible when the seal resistance is at least 5 times larger than the input resistance of the targeted cell. Measurement of E(m) under conditions in which the main background current includes a markedly nonlinear K(+) conductance (due to inward rectification) yields complex and somewhat counter-intuitive findings. In fact, there are at least two possible stable values of resting membrane potential for a cell when the nonlinear, inwardly rectifying K(+) conductance interacts with the seal current. This type of bistable behavior has been reported in a variety of small mammalian cells, including those from the heart, endothelium, smooth muscle and bone. Our theoretical treatment of these two common experimental situations provides useful mechanistic insights, and suggests practical methods by which these significant limitations, and their impact, can be minimized. Source

McKeough A.,University of Calgary
New directions for child and adolescent development | Year: 2011

Research has shown that a hallmark of adolescent development is the growing capacity to interpret human intentionality. In this chapter, the authors examine developmental change in this capacity, which they have termed interpretive thought, in two types of stories, family and autobiographical, told by Canadian youth aged ten to seventeen years. Illustrative examples reveal that youth coordinate an increasing number of psychological components and in so doing, create increasingly abstract and coherent psychological profiles of self and others. Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company. Source

Van Eck C.L.,Radboud University Nijmegen | Brown J.C.,University of Calgary | Shukurov A.,Northumbria University | Fletcher A.,Northumbria University
Astrophysical Journal | Year: 2015

Both observations and modeling of magnetic fields in the diffuse interstellar gas of spiral galaxies are well developed, but the theory has been confronted with observations for only a handful of individual galaxies. There is now sufficient data to consider the statistical properties of galactic magnetic fields. We have collected data from the literature on the magnetic fields and interstellar media of 20 spiral galaxies, and tested for various physically motivated correlations between magnetic field and interstellar medium parameters. Clear correlations emerge between the total magnetic field strength and molecular gas density as well as the star formation rate. The magnetic pitch angle exhibits correlations with the total gas density, the star formation rate, and the strength of the axisymmetric component of the mean magnetic field. The total and mean magnetic field strengths exhibit a noticeable degree of correlation, suggesting a universal behavior of the degree of order in galactic magnetic fields. We also compare the predictions of galactic dynamo theory to observed magnetic field parameters and identify directions in which theory and observations might be usefully developed. © 2015. The American Astronomical Society. All rights reserved. Source

Einsiedel E.F.,University of Calgary
OMICS A Journal of Integrative Biology | Year: 2011

Vaccines have been among the most effective tools for addressing global public health challenges. With the advent of genomics, novel approaches for vaccine discovery are opening up new opportunities for vaccine development and applications, particularly with the expectation of personalized vaccines and the possibility of addressing a broader range of infectious diseases. In this context, it is useful to reflect on the social contexts of vaccine development as these have been influenced by social, ethical, political challenges. This article discusses the historical context of vaccine controversies and factors that help explain public acceptance and resistance, illustrating that these challenges go well beyond simple public misunderstandings. The broader vaccine challenges evident along the innovation trajectory, from development to commercialization and implementation include problems in research and development, organizational issues, and legal and regulatory challenges that may collectively contribute to public resistance or confidence. The recent history of genomics provides further lessons that the developing field of vaccinomics can learn from. © Copyright 2011, Mary Ann Liebert, Inc. Source

Smooth muscle contraction is activated primarily by phosphorylation at S19 of the 20-kDa regulatory light chain subunits of myosin II (LC 20) catalyzed by Ca 2+/calmodulin-dependent myosin light chain kinase. Other kinases, for example, integrinlinked kinase (ILK), Rho-associated kinase (ROCK), and zipper-interacting protein kinase (ZIPK), can phosphorylate T18 in addition to S19, which increases the actin-activated myosin MgATPase activity at subsaturating actin concentrations ∼3-fold. These phosphorylatable residues and the amino acid sequence surrounding them are highly conserved throughout the animal kingdom; they are also found in an LC 20 homolog within the genome of Monosiga brevicollis, the closest living relative of metazoans. LC 20 diphosphorylation has been detected in mammalian vascular smooth muscle tissues in response to specific contractile stimuli and in pathophysiological situations associated with hypercontractility. LC 20 diphosphorylation has also been observed frequently in cultured cells where it activates force generation. Kinases such as ILK, ROCK, and ZIPK, therefore, are potential therapeutic targets in the treatment of, for example, cerebral vasospasm following subarachnoid hemorrhage and atherosclerosis. © 2011 IUBMB. Source

Phillipson M.,Uppsala University | Kubes P.,University of Calgary
Nature Medicine | Year: 2011

Here we focus on how neutrophils have a key regulatory role in vascular inflammation. Recent studies using advanced imaging techniques have yielded new insights into the mechanisms by which neutrophils contribute to defense against bacterial infections and also against sterile injury. In these settings, neutrophils are recruited by various mechanisms depending on the situation. We also describe how these processes may be disrupted in systemic infections, with a particular emphasis on mouse models of sepsis. Neutrophils are often immobilized in the lungs and liver during systemic infections, and this immobilization may be a mechanism through which bacteria can evade the innate immune response or allow neutrophils to form neutrophil extracellular traps that trap and kill bacteria in blood. The platelet is also an important player in sepsis, and we describe how it collaborates with neutrophils in the formation of neutrophil extracellular traps. © 2011 Nature America, Inc. All rights reserved. Source

Ter Keurs H.E.D.J.,University of Calgary
Pflugers Archiv European Journal of Physiology | Year: 2011

The macroscopic hallmarks of the normal heartbeat are rapid onset of contraction and rapid relaxation and an inotropic response to both increased end diastolic volume and increased heart rate. At the microscopic level, the calcium ion (Ca 2+) plays a crucial role in normal cardiac contraction. This paper reviews the cycle of Ca 2+ fluxes during the normal heartbeat, which underlie the coupling between excitation and contraction (ECC) and permit a highly synchronized action of cardiac sarcomeres. Length dependence of the response of the regulatory sarcomeric proteins mediates the Frank-Starling Law of the heart. However, Ca 2+ transport may go astray in heart disease and both jeopardize the exquisite mechanism of systole and diastole and triggering arrhythmias. The interplay between weakened and strong segments in nonuniform cardiac muscle may further lead to mechanoelectric feedback-or reverse excitation contraction coupling (RECC) mediating an early diastolic Ca 2+ transient caused by the rapid force decrease during the relaxation phase. These rapid force changes in nonuniform muscle may cause arrhythmogenic Ca 2+ waves to propagate by activation of neighbouring SR by diffusing Ca 2+ ions. © 2011 Springer-Verlag. Source

Trotter M.J.,University of Calgary
Clinics in Laboratory Medicine | Year: 2011

Primary cutaneous melanoma is treated by excisional surgery and careful histologic assessment of the specimen margins is a crucial component of pathology reporting. Surgical margins may be assessed by conventional transverse (bread-loaf) vertical sections, by en face vertical sections, or by en face oblique sections. Transverse techniques only sample a small percentage of the surgical margin. En face techniques are technically challenging but allow assessment of close to 100% of the margin. Margin assessment for melanoma removed from chronically sun-damaged skin is difficult. Melanoma in situ shows contiguous melanocyte growth, nesting, or intraepidermal pagetoid spread. Pitfalls include solar melanocytic hyperplasia, solar lentigines, melanocytic hyperplasia secondary to previous biopsy, lichenoid reactions, and invasive melanoma mimicking scar or benign nevus. En face sections can be used to assess margins for melanoma on sun-damaged skin, and evidence suggests that frozen sections may also be employed by experienced clinicians. Immunohistochemistry is a useful ancillary technique, enabling more accurate identification of in situ melanoma within a surgical margin. © 2011 Elsevier Inc. Source

Barclay R.M.R.,University of Calgary
PLoS ONE | Year: 2012

Many organisms produce offspring with sex-ratios that deviate from equal numbers of males and females, and numerous adaptive explanations have been proposed. In some species, offspring sex-ratio varies across the reproductive season, again with several explanations as to why this might be adaptive. However, patterns for birds and mammals are inconsistent, and multiple factors are likely involved. Long-term studies on a variety of species may help untangle the complexity. I analyzed a long-term data set on the variation in offspring sex-ratio of the big brown bat, Eptesicus fuscus, a temperate-zone, insectivorous species. Sex ratio varied seasonally, but only in some years. Births early in the season were significantly female biased in years in which parturition occurred relatively early, but not in years with late parturition. Survival of female pups increased with earlier median birth date for the colony, and early-born females were more likely to survive and reproduce as one-year olds, compared to later-born pups. I argue that, due to the unusual timing of reproductive activities in male and female bats that hibernate, producing female offspring early in the year increases their probability of reproducing as one year olds, but this is not the case for male offspring. Thus, mothers that can give birth early in the year, benefit most by producing a female pup. The relative benefit of producing female or male offspring varies depending on the length of the growing season and thus the time available for female pups to reach sexual maturity. This suggests that not only does sex-ratio vary seasonally and among years, depending on the condition of the mother and the environment, but also likely varies geographically due to differences in season length. © 2012 Robert M. R. Barclay. Source

McDougall J.J.,University of Calgary
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2011

Pain is a complex biological phenomenon that encompasses intricate neurophysiological, behavioural, psychosocial and affective components. Protracted or chronic pain alerts an individual to a possible pathological abnormality and is the main reason why patients visit a primary care physician. Despite the pervasiveness of chronic pain in the population, the effectiveness of current pharmacological therapies remains woefully inadequate and prolonged treatment often leads to the development of undesirable side-effects. Since the vast majority of chronic pain originates in a specific tissue or group of tissues, it may be advantageous to target pain control in the periphery and thereby circumvent the known risks associated with non-specific systemic treatments. This review spotlights a number of promising targets for peripheral pain control including the transient receptor potential (TRP) family of neuronal ion channels, the family of proteinase activated receptors (PARs), cannabinoids, and opioids. A critical appraisal of these targets in preclinical models of disease is given and their suitability as future peripheral analgesics is discussed. © 2010 Elsevier B.V. Source

Grewal S.S.,University of Calgary
F1000 Biology Reports | Year: 2012

The question of how growth and size are controlled has fascinated generations of biologists. However, the underlying mechanisms still remain unclear. The last year or so has seen a flurry of reports on the control of growth and body size in Drosophila, and a central theme to these papers is the idea of signaling between organs as a control mechanism for overall body growth and development. While this concept is obviously not new, these fly studies now open up the possibility of using a genetically tractable system to dissect in detail how organ-to-organ communication dictates body size. © 2012 Faculty of 1000 Ltd. Source

Friedenreich C.M.,Alberta Health Services Cancer Care | Friedenreich C.M.,University of Calgary
Recent Results in Cancer Research | Year: 2011

Breast cancer is the most commonly diagnosed invasive malignancy and the second leading cause of cancer death in women globally. This review considers epidemiologic evidence regarding the association between physical activity and breast cancer risk. Across these studies there was a 25% average risk reduction among physically active women as compared to the least active women. The associations were strongest for recreational activity, for activity sustained over the lifetime or done after menopause, and for activity that is of moderate to vigorous intensity and performed regularly. There is also some evidence for a stronger effect of physical activity among postmenopausal women, women who are normal weight, have no family history of breast cancer, and are parous. It is likely that physical activity is associated with decreased breast cancer risk via multiple interrelated biologic pathways that may involve adiposity, sex hormones, insulin resistance, adipokines, and chronic inflammation. Future research should include prospective observational epidemiologic studies relating proposed biomarkers to breast cancer risk and also randomized controlled trials to examine how physical activity influences the proposed biomarkers. Exercise trials will provide more clarity regarding the appropriate type, dose, and timing of activity that are related to breast cancer risk reduction. Breast cancer remains a leading cause of cancer incidence and mortality in most developed countries worldwide. While significant international research has examined risk factors for breast cancer, most identified risk factors are nonmodifiable. During the past 20 years, over 90 studies have been conducted worldwide that have examined some aspects of the association between physical activity and breast cancer risk reduction. The purpose of this chapter is to review both the epidemiologic evidence and hypothesized biologic mechanisms whereby physical activity may influence breast cancer risk. © 2010 Springer Berlin Heidelberg. Source

Huang S.,University of Calgary
Seminars in Cancer Biology | Year: 2011

The cracks in the paradigm of oncogenic mutations and somatic evolution as driving force of tumorigenesis, lucidly exposed by the dynamic heterogeneity of " cancer stem cells" or the diffuse results of cancer genome sequencing projects, indicate the need for a more encompassing theory of cancer that reaches beyond the current proximate explanations based on individual genetic pathways. One such integrative concept, derived from first principles of the dynamics of gene regulatory networks, is that cancerous cell states are attractor states, just like normal cell types are. Here we extend the concept of cancer attractors to illuminate a more profound property of cancer initiation: its inherent inevitability in the light of metazoan evolution. Using Waddington's Epigenetic Landscape as a conceptual aid, for which we present a mathematical and evolutionary foundation, we propose that cancer is intrinsically linked to ontogenesis and phylogenesis. This explanatory rather than enumerating review uses a formal argumentation structure that is atypical in modern experimental biology but may hopefully offer a new coherent perspective to reconcile many conflicts between new findings and the old thinking in the categories of linear oncogenic pathways. © 2011 Elsevier Ltd. Source

MacCallum J.L.,State University of New York at Stony Brook | Tieleman D.P.,University of Calgary
Trends in Biochemical Sciences | Year: 2011

The partitioning of amino acid sidechains into the membrane is a key aspect of membrane protein folding. However, lipid bilayers exhibit rapidly changing physicochemical properties over their nanometer-scale thickness, which complicates understanding the thermodynamics and microscopic details of membrane partitioning. Recent data from diverse approaches, including protein insertion by the Sec translocon, folding of a small beta-barrel membrane protein and computer simulations of the exact distribution of a variety of small molecules and peptides, have joined older hydrophobicity scales for membrane protein prediction. We examine the correlations among the scales and find that they are remarkably correlated even though there are large differences in magnitude. We discuss the implications of these scales for understanding membrane protein structure and function. © 2011 Elsevier Ltd. Source

Mang C.S.,University of Calgary
Medicine and Science in Sports and Exercise | Year: 2016

INTRODUCTION: In previous work, acute high-intensity aerobic exercise benefited continuous motor sequence task learning. As memory processes underlying motor sequence learning vary between tasks involving continuous and discrete movements, the objective of the current study was to determine if the beneficial effects of acute aerobic exercise generalize to the learning of a discrete motor sequence task. METHODS: Sixteen young healthy individuals practiced a discrete motor sequence task preceded by either a period of rest or a bout of high-intensity cycling. Participants moved a cursor with a computer mouse to a series of discretely-presented targets on a screen. Target presentation followed either a repeated or random sequence, which allowed evaluation of implicit sequence-specific motor learning. Change in movement response time over practice ([INCREMENT]-ACQ) and from practice to a 24-hour ‘no-exercise’ retention test ([INCREMENT]-RET), as well as rate of improvement over practice (α-ACQ) and during the retention test (α-RET) were calculated. RESULTS: α-RET was greater for the repeated sequence than random sequences following aerobic exercise (p = .01), but not rest (p = .33). Further, α-RET for the repeated sequence was greater following aerobic exercise than for either sequence (repeated, random) in the rest condition (p ≤ .01). There were no differences between sequences and/or conditions for [INCREMENT]-ACQ, [INCREMENT]-RET or α-RET (p ≥ .57). CONCLUSION: Our findings show a positive effect of acute high-intensity aerobic exercise on implicit discrete motor sequence learning. Performing exercise prior to practice increased the rate of improvement at a 24-hour delayed retention test, suggesting an impact on the rate of motor memory retrieval. Pairing acute aerobic exercise with motor practice may facilitate learning of discrete movement sequences in sport or rehabilitation settings. © 2016 American College of Sports Medicine Source

Ramachandran R.,University of Calgary
Discovery medicine | Year: 2012

Proteinase Activated Receptors (PARs) are G-protein coupled receptors (GPCRs) that were discovered in the early 1990's. They are unusual among GPCRs in being activated through proteolytic cleavage of the receptor N-terminus by serine proteinases such as thrombin. Over the last two decades major advances have been made in our understanding of how these receptors function and the roles they play in (patho)physiology. They have also emerged as drug targets for a number of conditions, most notably thrombosis. Recently two different drugs targeting PAR1 have entered clinical trials as anti-platelet agents. This review provides an overview of the proteinase activated receptor family and focuses on the role of PAR1 in regulating the endothelial barrier integrity and its implication on developing PAR antagonists for anti-platelet therapy. Source

Altier C.,University of Calgary
Sub-cellular biochemistry | Year: 2012

Voltage-gated ion channels are transmembrane proteins that control nerve impulses and cell homeostasis. Signaling molecules that regulate ion channel activity and density at the plasma membrane must be specifically and efficiently coupled to these channels in order to control critical physiological functions such as action potential propagation. Although their regulation by G-protein receptor activation has been extensively explored, the assembly of ion channels into signaling complexes of GPCRs plays a fundamental role, engaging specific downstream -signaling pathways that trigger precise downstream effectors. Recent work has confirmed that GPCRs can intimately interact with ion channels and serve as -chaperone proteins that finely control their gating and trafficking in subcellular microdomains. This chapter aims to describe examples of GPCR-ion channel co-assembly, focusing mainly on signaling complexes between GPCRs and voltage-gated calcium channels. Source

Boiko I.M.,University of Calgary
Proceedings of the American Control Conference | Year: 2011

It has been a widely accepted notion that approximation of discontinuous control by certain continuous function in a boundary layer results in chattering elimination in sliding mode (SM) control systems. It is shown through three different types of analysis that in the presence of parasitic dynamics, this approach to chattering elimination would work only if the slope of the continuous nonlinear function within the boundary layer is low enough, which may result in the deterioration of performance of the system. A few examples are provided. © 2011 AACC American Automatic Control Council. Source

Ghosh J.,University of Calgary
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

Quantum walk (QW) on a disordered lattice leads to a multitude of interesting phenomena, such as Anderson localization. While QW has been realized in various optical and atomic systems, its implementation with superconducting qubits still remains pending. The major challenge in simulating QW with superconducting qubits emerges from the fact that on-chip superconducting qubits cannot hop between two adjacent lattice sites. Here we overcome this barrier and develop a gate-based scheme to realize the discrete time QW by placing a pair of qubits on each site of a one-dimensional (1D) lattice and treating an excitation as a walker. It is also shown that various lattice disorders can be introduced and fully controlled by tuning the qubit parameters in our quantum walk circuit. We observe a distinct signature of transition from the ballistic regime to a localized QW with an increasing strength of disorder. Finally, an eight-qubit experiment is proposed where the signatures of such localized and delocalized regimes can be detected with existing superconducting technology. Our proposal opens up the possibility of exploring various quantum transport processes with promising superconducting qubits. © 2014 American Physical Society. Source

Davidsen J.,University of Calgary | Kwiatek G.,German Research Center for Geosciences
Physical Review Letters | Year: 2013

We examine the temporal statistics of micro-, nano-, and picoseismicity induced by mining as well as by long-term fluid injection. Specifically, we analyze catalogs of seismic events recorded at the Mponeng deep gold mine, South Africa, and at the German deep drilling site. We show that the distribution of time intervals between successive earthquakes is form invariant between the different catalogs. In particular, the distribution can be described by the same scaling function recently established for tectonic seismicity and acoustic emissions from laboratory rock fracture. Thus, our findings bridge the energy gap between those two cases and provide clear evidence that these temporal features of seismicity are independent of the energy scales of the events and whether they are of tectonic or induced origin. © 2013 American Physical Society. Source

Sandborn W.J.,University of California at San Diego | Ghosh S.,University of Calgary | Panes J.,Institute dInvestigacions Biomediques August Pi i Sunyer | Vranic I.,Pfizer | Rousell S.,Pfizer
New England Journal of Medicine | Year: 2012

Background: Ulcerative colitis is a chronic inflammatory disease of the colon for which current treatments are not universally effective. One additional treatment may be tofacitinib (CP-690,550), an oral inhibitor of Janus kinases 1, 2, and 3 with in vitro functional specificity for kinases 1 and 3 over kinase 2, which is expected to block signaling involving gamma chain-containing cytokines including interleukins 2, 4, 7, 9, 15, and 21. These cytokines are integral to lymphocyte activation, function, and proliferation. Methods: In a double-blind, placebo-controlled, phase 2 trial, we evaluated the efficacy of tofacitinib in 194 adults with moderately to severely active ulcerative colitis. Patients were randomly assigned to receive tofacitinib at a dose of 0.5 mg, 3 mg, 10 mg, or 15 mg or placebo twice daily for 8 weeks. The primary outcome was a clinical response at 8 weeks, defined as an absolute decrease from baseline in the score on the Mayo scoring system for assessment of ulcerative colitis activity (possible score, 0 to 12, with higher scores indicating more severe disease) of 3 or more and a relative decrease from baseline of 30% or more with an accompanying decrease in the rectal bleeding subscore of 1 point or more or an absolute rectal bleeding subscore of 0 or 1. Results: The primary outcome, clinical response at 8 weeks, occurred in 32%, 48%, 61%, and 78% of patients receiving tofacitinib at a dose of 0.5 mg (P = 0.39), 3 mg (P = 0.55), 10 mg (P = 0.10), and 15 mg (P<0.001), respectively, as compared with 42% of patients receiving placebo. Clinical remission (defined as a Mayo score ≤2, with no subscore >1) at 8 weeks occurred in 13%, 33%, 48%, and 41% of patients receiving tofacitinib at a dose of 0.5 mg (P = 0.76), 3 mg (P = 0.01), 10 mg (P<0.001), and 15 mg (P<0.001), respectively, as compared with 10% of patients receiving placebo. There was a dose-dependent increase in both low-density and high-density lipoprotein cholesterol. Three patients treated with tofacitinib had an absolute neutrophil count of less than 1500. Conclusions: Patients with moderately to severely active ulcerative colitis treated with tofacitinib were more likely to have clinical response and remission than those receiving placebo. (Funded by Pfizer; ClinicalTrials.gov number, NCT00787202.) Copyright © 2012 Massachusetts Medical Society. Source

Johal H.,University of Calgary
Journal of orthopaedic trauma | Year: 2014

Each year, 1.24 million people die as a result of road traffic collisions around the world, and millions more are left to suffer the resultant disabilities of their nonfatal typically musculoskeletal injuries. The most productive members of society are the ones affected the most, and the subsequent economic impact cannot be ignored. Reducing the morbidity and mortality associated with road traffic injuries will reduce suffering and increase available resources that can be used more effectively. Road traffic injuries are preventable, and the impact of those that do occur can be mitigated. Adequate national and global funding, strategy, and measurable targets are fundamental to a sustainable response to road safety. Over the last decade, the United Nations and World Health Organization have been part of the gaining momentum toward addressing this issue, through resolutions and coordinating global efforts. This is what brought about the "Decade of Action for Road Traffic Safety," and as orthopaedic surgeons, our involvement is key for the collaborative public health response toward this effort. Source

Barlow K.M.,University of Calgary
Handbook of Clinical Neurology | Year: 2013

In childhood, traumatic brain injury (TBI) poses the unique challenges of an injury to a developing brain and the dynamic pattern of recovery over time, inflicted TBI and its medicolegal ramifications. The mechanisms of injury vary with age, as do the mechanisms that lead to the primary brain injury. As it is common, and is the leading cause of death and disability in the USA and Canada, prevention is the key, and we may need increased legislation to facilitate this. Despite its prevalence, there is an almost urgent need for research to help guide the optimal management and improve outcomes. Indeed, contrary to common belief, children with severe TBI have a worse outcome and many of the consequences present in teenage years or later. The treatment needs, therefore, to be multifaceted and starts at the scene of the injury and extends into the home and school. In order to do this, the care needs to be multidisciplinary from specialists with a specific interest in TBI and to involve the family, and will often span many decades. © 2013 Elsevier B.V. Source

Tamara P.,University of Calgary
Handbook of Clinical Neurology | Year: 2013

Tourettte syndrome (TS) is a common, childhood onset neuropsychiatric disorder consisting of multiple motor and one or more vocal tics which persist for more than 1 year. Comorbid psychiatric diagnoses are frequent in this patient population, including attention-deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Tics can be simple or complex, and have a tendency to change over time. Tics are preceded by a premonitory sensation, wax and wane in frequency, and are often exacerbated by stress or excitement. Tic severity usually peaks in childhood, and improves in early adulthood. TS is a highly heritable disorder with a polygenic inheritance. The fundamental pathophysiology of TS is not known, although existing evidence suggests that it involves dysfunction of the basal ganglia and frontal cortical circuits, as well as dopaminergic neurotransmission. Treatment of TS involves consideration of symptom severity and comorbidity. In general, comorbid ADHD and OCD lead to greater disability in these patients, and therefore are the initial treatment priority. As treatment for tics does not alter the natural history of the disorder, it is only recommended if the tics are causing disability. Effective treatments to suppress tics include α-adrenergic agonists and antipsychotic medications. © 2013 Elsevier B.V. Source

Patten S.B.,University of Calgary
BMC Psychiatry | Year: 2013

Background: Major depression is a widely used diagnostic category but there is increasing dissatisfaction with its performance. The diathesis-stress model is an alternative approach that does not require the (sometimes arbitrary) imposition of categories onto the spectrum of depressive morbidity. However, application of this model has not been well explored and its consistency with available epidemiologic data is uncertain.Methods: Simulation provides an opportunity to explore these issues. In this study, a simulation model based on an intuitive representation of diathesis-stress interaction was developed. Both diathesis and stress were represented using continuous distributions, without categorization. A diagnostic threshold was then applied to the simulation output to create nominal categories and to explore their consistency with available information.Results: An apparently complex epidemiologic pattern emerged from the diathesis-stress interaction when thresholds were applied: incidence was time dependent, recurrence depended on the number of past episodes, baseline symptoms were associated with an increased risk of subsequent episodes and the remission rate declined with increasing episode duration.Conclusions: A diathesis-stress conceptualization coupled with application of a threshold-based diagnostic definition may explain several of the apparent complexities of major depression epidemiology. Some of these complexities may be artifacts of the nominal diagnostic approach. These observations should encourage an empirical exploration of whether diathesis-stress interactions provide a more parsimonious framework for understanding depression than current approaches. © 2013 Patten; licensee BioMed Central Ltd. Source

Shearer J.,University of Calgary | Graham T.E.,University of Guelph
Nutrition Reviews | Year: 2014

This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle. © 2014 International Life Sciences Institute. Source

Bonni S.,University of Calgary | Bonni A.,Harvard University
FEBS Letters | Year: 2012

The transcriptional regulator SnoN plays a fundamental role as a modulator of transforming growth factor beta (TGFβ)-induced signal transduction and biological responses. In recent years, novel functions of SnoN have been discovered in both TGFβ-dependent and TGFβ-independent settings in proliferating cells and postmitotic neurons. Accumulating evidence suggests that SnoN plays a dual role as a corepressor or coactivator of TGFβ-induced transcription. Accordingly, SnoN exerts oncogenic or tumor-suppressive effects in epithelial tissues. At the cellular level, SnoN antagonizes or mediates the ability of TGFβ to induce cell cycle arrest in a cell-type specific manner. SnoN also exerts key effects on epithelial-mesenchymal transition (EMT), with implications in cancer biology. Recent studies have expanded SnoN functions to postmitotic neurons, where SnoN orchestrates key aspects of neuronal development in the mammalian brain, from axon growth and branching to neuronal migration and positioning. In this review, we will highlight our understanding of SnoN biology at the crossroads of cancer biology and neurobiology. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved. Source

The permanent nature of motor deficits is a consistent cornerstone of cerebral palsy definitions. Such pessimism is disheartening to children, families, and researchers alike and may no longer be appropriate for it ignores the fantastic plastic potential of the developing brain. Perinatal stroke is presented as the ideal human model of developmental neuroplasticity following distinct, well-defined, focal perinatal brain injury. Elegant animal models are merging with human applied technology methods, including noninvasive brain stimulation for increasingly sophisticated models of plastic motor development following perinatal stroke. In this article, how potential central therapeutic targets are identified and potentially modulated to enhance motor function within these models is discussed. Also, future directions and emerging clinical trials are reviewed. © 2013 Elsevier Inc. Source

Desai J.A.,Foothills Medical Center | Smith E.E.,University of Calgary
Current Atherosclerosis Reports | Year: 2013

In acute ischemic stroke, time is brain. Current guidelines recommend that the time from arrival at hospital to initiation of administration of tissue plasminogen activator, also known as the door-to-needle (DTN) time, should be 60 min or less. However, DTN times in practice usually exceed this recommended time. The median DTN times from the American Heart Association/American Stroke Association Get With The Guidelines-Stroke program and the multinational Safe Implementation of Treatment in Stroke International Stroke Thrombolysis Register are 75 min and 65 min, respectively. Prehospital factors associated with delays include patient-related factors such as poor recognition of stroke symptoms, poor use of emergency medical services, and complex psychosocial factors. Accurate recognition of stroke symptoms at a dispatcher and paramedic level is associated with shorter onset-to-arrival times. Prenotification of regional stroke centers by paramedics is strongly associated with shorter DTN times. In-hospital delays resulting in prolonged DTN times can be attenuated by having well-defined rapid triage pathways, defined stroke teams, single-call stroke team activation, established code stroke protocols, rapid access to diagnostic imaging, and laboratory services. In this review we summarize factors associated with prolonged DTN times and processes that allow faster onset-to-treatment times. Recent developments in the field are highlighted. © 2013 Springer Science+Business Media New York. Source

Turner R.J.,University of Calgary | Borghese R.,University of Bologna | Zannoni D.,University of Bologna
Biotechnology Advances | Year: 2012

Here, we overview the most recent advances in understanding the bacterial mechanisms that stay behind the reduction of tellurium oxyanions in both planktonic cells and biofilms. This is a topic of interest for basic and applied research because microorganisms are deeply involved in the transformation of metals and metalloids in the environment. In particular, the recent observation that toxic tellurite can be precipitated either inside or outside the cells being used as electron sink to support bacterial growth, opens new perspectives for both microbial physiologists and biotechnologists. As promising nanomaterials, tellurium based nanoparticles show unique electronic and optical properties due to quantum confinement effects to be used in the area of chemistry, electronics, medicine and environmental biotechnologies. © 2011 Elsevier Inc. Source

Lockyer J.,University of Calgary
Journal of Continuing Education in the Health Professions | Year: 2013

Introduction: High-quality instruments are required to assess and provide feedback to practicing physicians. Multisource feedback (MSF) uses questionnaires from colleagues, coworkers, and patients to provide data. It enables feedback in areas of increasing interest to the medical profession: communication, collaboration, professionalism, and interpersonal skills. The purpose of the study was to apply the 7 assessment criteria as a framework to examine the quality of MSF instruments used to assess practicing physicians. Methods: The criteria for assessment (validity, reproducibility, equivalence, feasibility, educational effect, catalytic effect, and acceptability) were examined for 3 sets of instruments, drawing on published data. Results: Three MSF instruments with a sufficient body of research for inclusion-the Canadian Physician Achievement Review instruments and the United Kingdom's GMC and CFEP360 instruments-were examined. There was evidence that MSF has been assessed against all criteria except educational effects, although variably for some of the instruments. The greatest emphasis was on validity, reproducibility, and feasibility for all of the instruments. Assessments of the catalytic effect were not available for 1 of the 2 UK instruments and minimally examined for the other. Data about acceptability are implicit in the UK instruments from their endorsement by the Royal College of General Practice and explicitly examined in the Canadian instruments. Discussion: The 7 criteria provided a useful framework to assess the quality of MSF instruments and enable an approach to analyzing gaps in instrument assessment. These criteria are likely to be helpful in assessing other instruments used in medical education. © 2013 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on CME, Association for Hospital Medical Education. Source

Naugler C.,University of Calgary
Canadian Family Physician | Year: 2013

Objective To determine the relative effects of population size, FP and GP supply, and other specialist supply on chemistry and hematology test volumes (ie, number of tests performed). Design Population-level analysis using secondary data from the Calgary Health Zone for 2004 to 2009. Setting Calgary, Alta. Main outcome measures The relative effects of population size, FP and GP supply, and other specialist supply on laboratory test use. Results Population size was the strongest predictor of test volumes in a multivariate analysis. The FP and GP supply was significantly negatively correlated with chemistry test volume (partial r2 = 0.186, P = .045). There was a trend toward decreasing use of hematology tests with increasing FP and GP supply (partial r2 = 0.117, P = .119). Conclusion The relationship between FP and GP supply and laboratory test use is complex, but increasing numbers of FPs do not necessarily indicate an increase in laboratory test use and might be associated with a decrease in test use when other factors are controlled for. Source

Xue P.,Nanjing Southeast University | Sanders B.C.,University of Calgary
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We show that the standard quantum-walk quantum-to-classical transition, characterized by ballistic-to-diffusive spreading of the walker's position, can be controlled by externally modulating the coin state. We illustrate this by showing an oscillation between classical diffusive and quantum ballistic spreading using numerical and asymptotically exact closed-form solutions, and we prove that the walker is in a controllable incoherent mixture of classical and quantum walks with a reversible quantum-to-classical transition. © 2013 American Physical Society. Source

Froese D.S.,University of Oxford | Gravel R.A.,University of Calgary
Expert Reviews in Molecular Medicine | Year: 2010

Vitamin B 12 (cobalamin, Cbl) is an essential nutrient in human metabolism. Genetic diseases of vitamin B 12 utilisation constitute an important fraction of inherited newborn disease. Functionally, B 12 is the cofactor for methionine synthase and methylmalonyl CoA mutase. To function as a cofactor, B 12 must be metabolised through a complex pathway that modifies its structure and takes it through subcellular compartments of the cell. Through the study of inherited disorders of vitamin B 12 utilisation, the genes for eight complementation groups have been identified, leading to the determination of the general structure of vitamin B 12 processing and providing methods for carrier testing, prenatal diagnosis and approaches to treatment. © Cambridge University Press 2010. Source

Mahler M.,Dr Fooke Laboratorien | Fritzler M.J.,University of Calgary
Annals of the New York Academy of Sciences | Year: 2010

Autoimmune diseases are characterized by self-reactive immune processes mediated by B and T cells. These disorders exhibit a spectrum of clinical features that range from local or organ specific to systemic diseases. Although a variety of putative mechanisms that trigger the loss of tolerance and thus the genesis of autoimmunity have been identified, for the most part the precise mechanisms remain illusive. Nevertheless, it is widely appreciated that autoantibodies are useful both in the diagnosis of autoimmune disorders and as molecular biological tools to study cellular processes in which the target antigens are involved. Several methods and technologies, including protein fragments, synthetic peptides, phage display, or structural analyses have been developed for the characterization of the specificity of the autoimmune reactions. The present review provides an overview of the autoantibody epitopes in systemic autoimmune diseases as they relate to the clinical relevance and applications of certain autoepitopes and the technologies that are used to classify and identify them. © 2009 New York Academy of Sciences. Source

Fox J.W.,University of Calgary
Trends in Ecology and Evolution | Year: 2013

A leading idea about how disturbances and other environmental fluctuations affect species diversity is the intermediate disturbance hypothesis (IDH). The IDH states that diversity of competing species is, or should be expected to be, maximized at intermediate frequencies and/or intensities of disturbance or environmental change. I argue that the IDH has been refuted on both empirical and theoretical grounds, and so should be abandoned. Empirical studies only rarely find the predicted humped diversity-disturbance relationship. Theoretically, the three major mechanisms thought to produce humped diversity-disturbance relationships are logically invalid and do not actually predict what they are thought to predict. Disturbances and other environmental fluctuations can affect diversity, but for different reasons than are commonly recognized. © 2012 Elsevier Ltd. Source

Sidor M.M.,University of Pittsburgh | MacQueen G.M.,University of Calgary
Current Psychiatry Reports | Year: 2012

The effective treatment of depression in people with bipolar disorder remains a clinical challenge. The role of antidepressant medication in treating bipolar depression has been controversial. While early studies and meta-analyses supported a role for antidepressant medication, more recent, high quality randomized controlled trials in bipolar depression have generally not demonstrated efficacy for antidepressant medications. Although the risk of affective switch and longterm de-stabilization remains a concern when using antidepressant medications in bipolar disorder, the magnitude of this risk has been difficult to ascertain with confidence. Maintenance use of antidepressantmedication has generally not demonstrated a favorable risk-benefit ratio. Future studies should explore the patient characteristics and response patterns that predict a more favorable response profile to antidepressants amongst patients with bipolar disorder so that the medications can be rationally used in those who are most likely to benefit. © Springer Science+Business Media, LLC 2012. Source

Clarkson C.R.,University of Calgary
International Journal of Coal Geology | Year: 2013

Unconventional gas reservoirs, including coalbed methane (CBM), tight gas (TG) and shale gas (SG), have become a significant source of hydrocarbon supply in North America, and interest in these resource plays has been generated globally. Despite a growing exploitation history, there is still much to be learned about fluid storage and transport properties of these reservoirs.A key task of petroleum engineers and geoscientists is to use historical production (reservoir fluid production rate histories, and cumulative production) for the purposes of 1) reservoir and well stimulation characterization and 2) production forecasting for reserve estimation and development planning. Both of these subtasks fall within the domain of quantitative production data analysis (PDA). PDA can be performed analytically, where physical models are applied to historical production and flowing pressure data to first extract information about the reservoir (i.e. hydrocarbon-in-place, permeability-thickness product) and stimulation (i.e. skin or hydraulic fracture properties) and then generate a forecast using a model that has been "calibrated" to the dynamic data (i.e. rates and pressures). Analytical production data analysis methods, often referred to as rate-transient analysis (RTA), utilize concepts analogous to pressure-transient analysis (PTA) for their implementation, and hence have a firm grounding in the physics of fluid storage and flow. Empirical methods, such as decline curve analysis, rely on empirical curve fits to historical production data, and projections to the future. These methods do not rigorously account for dynamic changes in well operating conditions (i.e. flowing pressures), or reservoir or fluid property changes. Quantitative PDA is now routinely applied for conventional reservoirs, where the physics of fluid storage and flow are relatively well-understood. RTA has evolved extensively over the past four decades, and empirical methods are now applied with constraints and "rules of thumb" developed by researchers with some confidence. For unconventional reservoirs, these techniques continue to evolve according to our improved understanding of the physics of fluid storage and flow. In this article, the latest techniques for quantitative PDA including type-curve analysis, straight-line (flow-regime) analysis, analytical and numerical simulation and empirical methods are briefly reviewed, specifically addressing their adaptation for CBM and SG reservoirs. Simulated and field examples are provided to demonstrate application. It is hoped that this article will serve as practical guide to production analysis for unconventional reservoirs as well as reveal the latest advances in these techniques. © 2013 Elsevier B.V. Source

Production of bitumen by surface mining of Alberta's oil sands has given rise to tailings ponds, containing large volumes of finely dispersed clays (108 m3), which settle only slowly. The mature fine tailings (MFT) in these ponds are operationally defined as consisting of particles smaller than 44 μm with a solids content in excess of 30% (w/w). Increasing the rate of densification of MFT is a rate-limiting step in tailings pond reclamation. Accelerated densification has been achieved through mixing of MFT with sand in the presence of calcium sulfate as a binding agent to generate consolidated tailings. Addition of negatively charged polymer, together with either calcium or magnesium ions, is similarly effective. Although toxic to higher aquatic life, tailings ponds harbour a wide variety of mainly anaerobic microbes. These convert residual hydrocarbon, causing methane emissions of up to 104 m3 day-1. Interestingly, anaerobic microbial activity also accelerates tailings pond densification. Hence, many technologies designed to accelerate densification move tailings, at least conceptually, towards soil in which sand and clay particles are linked by large amounts of humic and fulvic acid polymers supporting large numbers of microbes in a mechanically stable structure. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 257-262, 2013. Copyright © 2012 Wiley Periodicals, Inc. Source

Marrink S.J.,Zernike Institute for Advanced Materials | Tieleman D.P.,University of Calgary
Chemical Society Reviews | Year: 2013

The Martini model, a coarse-grained force field for biomolecular simulations, has found a broad range of applications since its release a decade ago. Based on a building block principle, the model combines speed and versatility while maintaining chemical specificity. Here we review the current state of the model. We describe recent highlights as well as shortcomings, and our ideas on the further development of the model. © 2013 The Royal Society of Chemistry. Source

Are recreational fisheries resilient to harvest or prone to collapse? This paper reviews research published since that question was posed by Post et al. (2002, Fisheries 27, 6-17). A number of patterns and processes have been identified that suggest understanding the risk of collapse requires knowledge of the fishing effort response, degree of depensation in the fishery and the life history of the harvested species. Processes involving the behaviour of fish, behaviour of anglers and management responses to declining quality can all impact the degree of resilience of recreational fisheries and their risk of collapse. The spatial context of an individual fishery can be important as they are often embedded in lake districts and joined by mobile anglers so their local dynamics are not independent from other fisheries. Typical regulations that restrict the behaviour of individual anglers in open-access fisheries can provide some resilience but cannot prevent collapse if the fishing effort is too high. Many uncertainties remain related to the occurrence and intensity of the key processes and therefore adopting an adaptive experimental management approach might be the most useful approach to minimise the risk of collapse in recreational fisheries. © 2012 Blackwell Publishing Ltd. Source

McEwen B.S.,Rockefeller University | Bowles N.P.,Rockefeller University | Gray J.D.,Rockefeller University | Hill M.N.,University of Calgary | And 3 more authors.
Nature Neuroscience | Year: 2015

The brain is the central organ involved in perceiving and adapting to social and physical stressors via multiple interacting mediators, from the cell surface to the cytoskeleton to epigenetic regulation and nongenomic mechanisms. A key result of stress is structural remodeling of neural architecture, which may be a sign of successful adaptation, whereas persistence of these changes when stress ends indicates failed resilience. Excitatory amino acids and glucocorticoids have key roles in these processes, along with a growing list of extra- and intracellular mediators that includes endocannabinoids and brain-derived neurotrophic factor (BDNF). The result is a continually changing pattern of gene expression mediated by epigenetic mechanisms involving histone modifications and CpG methylation and hydroxymethylation as well as by the activity of retrotransposons that may alter genomic stability. Elucidation of the underlying mechanisms of plasticity and vulnerability of the brain provides a basis for understanding the efficacy of interventions for anxiety and depressive disorders as well as age-related cognitive decline. Source

Storek J.,University of Calgary | Mohty M.,University Pierre and Marie Curie | Boelens J.J.,University Utrecht
Biology of Blood and Marrow Transplantation | Year: 2015

Anti-T cell globulin (ATG) is polyclonal IgG from rabbits immunized with human thymocytes or a human T cell line. Prophylaxis using ATG infused with conditioning for adult marrow or blood stem cell transplantation reduces both acute and chronic graft-versus-host disease (GVHD). However, ATG is not or minimally efficacious in steroid refractory GVHD treatment. Regarding preemptive therapy, ATG is promising; however, further work is needed on establishing adequate biomarkers to be used as triggers for preemptive therapy before it can be used routinely. Relapse is not increased by ATG, except possibly in the setting of reduced-intensity conditioning. Infections are probably increased when using high but not low-dose ATG, except for Epstein-Barr virus-driven post-transplantation lymphoproliferative disorder, which may be increased even with low-dose ATG. Survival is not improved with ATG; however, survival free of immunosuppressive therapy is improved. Pharmacokinetics of ATG are highly variable, resulting in highly variable areas under the time-concentration curves. Optimized dosing of ATG might improve transplantation outcomes. In conclusion, ATG reduces GVHD and, thus, may improve quality of life, without compromising survival. © 2015 American Society for Blood and Marrow Transplantation. Source

Grisaru S.,University of Calgary
International Journal of Nephrology and Renovascular Disease | Year: 2014

Acute renal failure associated with a fulminant, life-threatening systemic disease is rare in previously healthy young children; however, when it occurs, the most common cause is hemolytic-uremic syndrome (HUS). In most cases (90%), this abrupt and devastating illness is a result of ingestion of food or drink contaminated with pathogens that produce very potent toxins. Currently, there are no proven treatment options that can directly inactivate the toxin or effectively interfere with the cascade of destructive events triggered by the toxin once it gains access to the bloodstream and binds its receptor. However, HUS is self-limited, and effective supportive management during the acute phase is proven to be a life saver for children affected by HUS. A minority of childhood HUS cases, approximately 5%, are caused by various genetic mutations causing uncontrolled activation of the complement system. These children, who used to have a poor prognosis leading to end-stage renal disease, now have access to exciting new treatment options that can preserve kidney function and avoid disease recurrences. This review provides a summary of the current knowledge on the epidemiology, pathophysiology, and clinical presentation of childhood HUS, focusing on a practical approach to best management measures. © 2014 Grisaru. Source

Wang R.,University of Calgary
International Journal of Image and Data Fusion | Year: 2013

3D modeling from images and LiDAR (Light Detection And Ranging) has been an active research area in the photogrammetry, computer vision, and computer graphics communities. In terms of literature review, a comprehensive survey on 3D building modeling that contains methods from all these fields will be beneficial. This article attempts to survey the state-of-the-art 3D building modeling methods in the areas of photogrammetry, computer vision, and computer graphics. The existing methods are grouped into three categories: 3D reconstruction from images, 3D modeling using range data, and 3D modeling using images and range data. The use of both data for 3D modeling is a sensor fusion approach, in which methods of image-to-LiDAR registration, upsampling, and image-guided segmentation are reviewed. For each category, the key problems are identified and solutions are addressed. © 2013 Copyright Taylor and Francis Group, LLC. Source

Duffy A.,University of Calgary
Canadian Journal of Psychiatry | Year: 2014

Objectives: To describe key findings relating to the natural history and heterogeneity of bipolar disorder (BD) relevant to the development of a unitary clinical staging model. Currently proposed staging models are briefly discussed, highlighting complementary findings, and a comprehensive staging model of BD is proposed integrating the relevant evidence. Method: A selective review of key published findings addressing the natural history, heterogeneity, and clinical staging models of BD are discussed. Results: The concept of BD has broadened, resulting in an increased spectrum of disorders subsumed under this diagnostic category. Different staging models for BD have been proposed based on the early psychosis literature, studies of patients with established BD, and prospective studies of the offspring of parents with BD. The overarching finding is that there are identifiable sequential clinical phases in the development of BD that differ in important ways between classical episodic and psychotic spectrum subtypes. In addition, in the context of familial risk, early risk syndromes add important predictive value and inform the staging model for BD. Conclusions: A comprehensive clinical staging model of BD can be derived from the available evidence and should consider the natural history of BD and the heterogeneity of subtypes. This model will advance both early intervention efforts and neurobiological research. Source

Jamaloei B.Y.,University of Calgary
Special Topics and Reviews in Porous Media | Year: 2013

In spite of the tremendous amount of work conducted on the evaluation of the drainage through porous media in different applications (e.g., soil remediation, nonaqueous phase removal, enhanced oil recovery, aquifer flow), a detailed review of these works in different contexts is missing from the literature. Thus, this extensive survey has been conducted with the hope to bridge the gap in information here. The aim of this study is to provide a detailed, comprehensive literature survey of the recent advances in the experimental study and modeling of drainage process in porous media. It is expected that this paper will serve as a reference tool for the engineers and scientists interested in the study of the drainage through porous media in different applications. © 2013 by Begell House, Inc. Source

Voordouw G.,University of Calgary
Current Opinion in Biotechnology | Year: 2011

Microbial activity in oil reservoirs is common. Methanogenic consortia hydrolyze low molecular weight components to methane and CO 2, transforming light oil to heavy oil to bitumen. The presence of sulfate in injection water causes sulfate-reducing bacteria to produce sulfide. This souring can be reversed by nitrate, stimulating nitrate-reducing bacteria. Removing biogenic sulfide is important, because it contributes to pitting corrosion and resulting pipeline failures. Increased water production eventually makes oil production uneconomic. Microbial fermentation products can lower oil viscosity or interfacial tension and produced biomass can block undesired flow paths to produce more oil. These biotechnologies benefit from increased understanding of reservoir microbial ecology through new sequence technologies and help to decrease the environmental impact of oil production. © 2010 Elsevier Ltd. Source

Zochodne D.W.,University of Calgary
ACS Chemical Neuroscience | Year: 2014

Neurons choose growth pathways with half hearted reluctance, behavior that may be appropriate to maintain fixed long lasting connections but not to regenerate them. We now recognize that intrinsic brakes on regrowth are widely expressed in these hesitant neurons and include classical tumor suppressor molecules. Here, we review how two brakes, PTEN (phosphatase and tensin homolog deleted on chromosome 10) and retinoblastoma emerge as new and exciting knockdown targets to enhance neuron plasticity and improve outcome from damage or disease. © 2014 American Chemical Society. Source

Riabowol K.,University of Calgary
FEBS Letters | Year: 2014

Cancer cells accumulate genetic and epigenetic changes that alter gene expression to drive tumorigenesis. Epigenetic silencing of tumor suppressor, cell cycle, differentiation and DNA repair genes contributes to neoplastic transformation. The ING (inhibitor of growth) proteins (ING1-ING5) have emerged as a versatile family of growth regulators, phospholipid effectors, histone mark sensors and core components of HDAC1/2 - and several HAT chromatin-modifying complexes. This review will describe the characteristic pathways by which ING family proteins differentially affect the Hallmarks of Cancer and highlight the various epigenetic mechanisms by which they regulate gene expression. Finally, we will discuss their potentials as biomarkers and therapeutic targets in epigenetic treatment strategies. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved. Source

El-Guebaly N.,University of Calgary
Journal of Addiction Medicine | Year: 2012

Objective: To review the evolution of the paradigm of recovery in addiction and its implications. Method: A systematic literature review was conducted using the MEDLINE and PsychInfo databases over the past 10 years and key references from the retrieved literature. Findings: The historical evolution of the concept of recovery has been shaped by several driving forces, including consumer experience, the need to better define our treatment outcome and parallel elaboration of the concepts of health, quality of life, and chronic disorders. Similarities and differences with the concept of "recovery" in mental health and other biomedical fields are identified. The empirical basis is growing in support of various proposed attributions and features of recovery along with the temporal benchmarks involved. The various forms of recovery, such as "natural," "transformational," or "medication-assisted," describe a choice of pathways to a common goal. The management implications are far-reaching and call for system shifts from acute stabilization to sustained recovery, including the growth of alternative institutions, and roles complementary to mutual help. Tools for the sustenance of recovery, including educational kits, recovery workbooks, and e-recovery initiatives, are developing. Conclusions: Although first-person accounts of recovery abound, a more systematic empirical investigation of the concept has just begun, including demographic and cultural differences. Management implications are derived from the experience with other "mainstream" chronic disorders with treatment providing stabilization and initiation of recovery and a range of long-term resources becoming available to sustain it. Copyright © 2012 American Society of Addiction Medicine. Source

Racher H.,University of Calgary
G3 (Bethesda, Md.) | Year: 2012

Stem cell populations are maintained by keeping a balance between self-renewal (proliferation) and differentiation of dividing stem cells. Within the Caenorhabditis elegans germline, the key regulator maintaining this balance is the canonical Notch signaling pathway, with GLP-1/Notch activity promoting the proliferative fate. We identified the Pumilio homolog, PUF-8, as an inhibitor of the proliferative fate of stem cells in the C. elegans germline. puf-8(0) strongly enhances overproliferation of glp-1(gf) mutants and partially suppresses underproliferation of a weak glp-1(lf) mutant. The germline tumor that is formed in a puf-8(0); glp-1(gf) double mutant is due to a failure of germ cells to enter meiotic prophase. puf-8 likely inhibits the proliferative fate through negatively regulating GLP-1/Notch signaling or by functioning parallel to it. Source

Herzog W.,University of Calgary
Journal of Applied Physiology | Year: 2014

In contrast to isometric and shortening contractions, many observations made on actively lengthening muscles cannot be readily explained with the sliding filament and cross-bridge theory. Specifically, residual force enhancement, the persistent increase in force following active muscle lengthening, beyond what one would expect based on muscle length, has not been explained satisfactorily. Here, we summarize the experimental evidence on residual force enhancement, critically evaluate proposed mechanisms for the residual force enhancement, and propose a mechanism for residual force enhancement that explains all currently agreed upon experimental observations. The proposed mechanism is based on the engagement of the structural protein titin upon muscle activation and an increase in titin's resistance to active compared with passive stretching. This change in resistance from the passive to the active state is suggested to be based on 1) calcium binding by titin upon activation, 2) binding of titin to actin upon activation, and 3) as a consequence of titin-actin binding - a shift toward stiffer titin segments that are used in active compared with passive muscle elongation. Although there is some experimental evidence for the proposed mechanism, it must be stressed that much of the details proposed here remain unclear and should provide ample research opportunities for scientists in the future. Nevertheless, the proposed mechanism for residual force enhancement explains all basic findings in this area of research. Copyright © 2014 the American Physiological Society. Source

Purpose: To assess the utility of "influenza-like illness" (ILI) and whether it appropriately tests influenza vaccine effectiveness. Principal results: The WHO and CDC definitions of "influenza-like illness" are similar. However many studies use other definitions, some not specifying a temperature and requiring specific respiratory and/or systemic symptoms, making many samples non-comparable. Most ILI studies find less than 25% of cases are RT-PCR-positive, those which test for other viruses and bacteria usually find multiple other pathogens, and most identify no pathogen in about 50% of cases. ILI symptom and symptom combinations do not have high sensitivity or specificity in identifying PCR-positive influenza cases. Rapid influenza diagnostic tests are increasingly used to screen ILI cases and they have low sensitivity and high specificity when compared to RT-PCR in identifying influenza. Main conclusions: The working diagnosis of ILI presumes influenza may be involved until proven otherwise. Health care workers would benefit by renaming the WHO and CDC ILI symptoms and signs as "acute respiratory illness" and also using the WHO acute severe respiratory illness definition if the illness is severe and meets this criterion. This renaming would shift attention to identify the viral and bacterial pathogens in cases and epidemics, identify new pathogens, implement vaccination plans appropriate to the identified pathogens, and estimate workload during the viral season. Randomised controlled trials testing the effectiveness of influenza vaccine require all participants to be assessed by a gold standard (RT-PCR). ILI has no role in measuring influenza vaccine effectiveness. ILI is well established in the literature and in the operational definition of many surveillance databases and its imprecise definition may be inhibiting progress in research and treatment. The current ILI definition could with benefit be renamed "acute respiratory illness," with additional definitions for "severe acute respiratory illness" (SARI) with RT-PCR testing for pathogens to facilitate prevention and treatment. © 2014 Elsevier Ltd. Source

Antao S.M.,University of Calgary
Powder Diffraction | Year: 2014

The crystal structure of a morimotoite garnet, ideally Ca3(Ti4+Fe2+)Si3O12, from the Ice River alkaline complex, British Columbia, Canada was refined by the Rietveld method, space group $Ia\overline 3 d$, and monochromatic synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Electron-microprobe analysis indicates a homogeneous sample with a formula {Ca2.91Mg0.05Mn2+ 0.03}Σ3[Ti1.09Fe3+ 0.46Fe2+ 0.37Mg0.08]Σ2(Si2.36Fe3+ 0.51Al0.14)Σ3O12. The HRPXRD data show a two-phase intergrowth. The reduced χ 2 and overall R(F 2) Rietveld refinement values are 1.572 and 0.0544, respectively. The weight percentage, unit-cell parameter (Å), distances (Å), and site occupancy factors (sofs) for phase-1 are as follows: 76.5(1)%, a = 12.156 98(1) Å, average  = 2.4383, Ti-O = 2.011(1), Si-O = 1.693(1) Å, Ca(sof) = 0.943(2), Ti(sof) = 0.966(2), and Si(sof) = 1.095(3). The corresponding values for phase-2 are 23.5(1)%, a = 12.160 67(2) Å, average  = 2.452, Ti-O = 1.988(3), Si-O = 1.704(3) Å, Ca(sof) = 1.063(7), Ti(sof) = 1.187(7), and Si(sof) = 1.220(8). The two phases cause strain that arises from structural mismatch and gives rise to low optical anisotropy. Because the two phases are structurally quite similar, a refinement using a single-phase model with anisotropic displacement parameters shows no unusual displacement ellipsoid for the O atom that requires a split O-atom position, as was done in previous studies. © International Centre for Diffraction Data 2014. Source

Prebiotic fibers are non-digestible carbohydrates that promote the growth of beneficial bacteria in the gut. Prebiotic consumption may benefit obesity and associated co-morbidities by improving or normalizing the dysbiosis of the gut microbiota. We evaluated the dose response to a prebiotic diet on the gut microbiota, body composition and obesity associated risk factors in lean and genetically obese rats. Prebiotic fibers increased Firmicutes and decreased Bacteroidetes, a profile often associated with a leaner phenotype. Bifidobacteria and Lactobacillus numbers also increased. Changes in the gut microbiota correlated with energy intake, glucose, insulin, satiety hormones, and hepatic cholesterol and triglyceride accumulation. Here we provide a comprehensive analysis evaluating the results through the lens of the gut microbiota. Salient, new developments impacting the interpretation and significance of our data are discussed. We propose that prebiotic fibers have promise as a safe and cost-effective means of modulating the gut microbiota to promote improved host:bacterial interactions in obesity and insulin resistance. Human clinical trials should be undertaken to confirm these effects. Source

Borio D.,University of Calgary
IEEE Transactions on Aerospace and Electronic Systems | Year: 2010

The extreme weakness of a global navigation satellite system (GNSS) signal makes it vulnerable to a wide variety of interfering signals, falling within the GNSS frequency bands. One of the main classes of these disturbing signals is represented by continuous wave interference (CWI), which include all signals that can be effectively represented as pure sinusoids. This paper deals with the performance of GNSS signal acquisition in the presence of CWI. An original model describing the impact of CWI on signal acquisition is proposed and the expressions of both false alarm and detection probabilities are mathematically formulated and validated by Monte Carlo simulations. The paper also investigates the role of the interference amplitude and frequency along with the impact of different system parameters on the detection and false alarm probabilities. © 2006 IEEE. Source

Garousi V.,University of Calgary
IEEE Transactions on Education | Year: 2010

Based on the demonstrated value of peer reviews in the engineering industry, numerous industry experts have listed it at the top of the list of desirable development practices. Experience has shown that problems (defects) are eliminated earlier if a development process incorporates peer reviews and that these reviews are as effective as or even more effective than testing. It is therefore important for engineering students to peer review each other's work during design projects. However, surprisingly, few engineering courses in universities and colleges include peer-review activities in their design projects. The author thus decided to incorporate peer reviews in the design project of a senior software engineering course in two offerings of the course. The purpose of this article is to present the experimental findings, lessons learned, possible challenges, and recommendations that may be used to promote learning and also the use of peer-review activities in teaching other software, electrical, and computer engineering courses. The results of the experiment show promising signs of using peer review in the design project of the course. © 2009 IEEE. Source

Bertram J.E.A.,University of Calgary
Current Biology | Year: 2015

Summary The way we walk determines the energetic investment needed. Humans spontaneously alter their walking style to exploit energetic opportunities. New research demonstrates the sensitivity and timing of this optimization and opens the door to discovering the underlying mechanisms. © 2015 Elsevier Ltd. Source

Kramer A.H.,University of Calgary
Seminars in Neurology | Year: 2015

Despite worldwide acceptance of the concept of brain death, there is marked variability in the use of ancillary testing. In most countries, ancillary tests are used primarily when confounding factors interfere with reliable completion of a clinical assessment, or physiologic instability precludes performance of an apnea test. Alternatively, in some countries, confirmatory ancillary tests are routinely required before brain death can be diagnosed. Ancillary tests assess brain function (e.g., electroencephalography) or blood flow (e.g., cerebral angiography). Evaluation of blood flow is affected less by confounding clinical factors and is now preferred in most jurisdictions. With angiographic techniques, a significant proportion of patients meeting clinical criteria for brain death have some opacification of proximal intracranial arteries. Consequently, the sensitivity of angiography is strongly influenced by the particular criteria that are used to define intracranial circulatory arrest. Lack of enhancement of the great cerebral and internal cerebral veins has the highest sensitivity. Worldwide experience with newer tests, such as computed tomography and magnetic resonance angiography, is growing. Radionuclide imaging has the advantage of not requiring use of potentially nephrotoxic contrast material. Transcranial Doppler ultrasonography can be brought to the bedside to demonstrate lack of brain blood flow. The specificity of imaging techniques in the detection of intracranial circulatory arrest has not been as well studied as their sensitivity. © 2015 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Source

Smith E.E.,University of Calgary | Schwamm L.H.,Massachusetts General Hospital
Stroke | Year: 2015

Endovascular acute ischemic stroke therapy is now proven by randomized controlled trials to produce large, clinically meaningful benefits. In response, stroke systems of care must change to increase timely and equitable access to this therapy. In this review, we provide a North American perspective on implications for stroke systems, focusing on the United States and Canada, accompanied by initial recommendations for changes. Most urgently, every community must create access to a hospital that can safely and quickly provide intravenous tissue-type plasminogen activator and immediately transfer appropriate patients onward to a more capable center as required. Safe and effective therapy in the community setting will be ensured by certification programs, performance measurement, and data entry into registries. © 2015 American Heart Association, Inc. Source

Ho M.,University of Calgary
Blood | Year: 2014

In this issue of Blood, Aird et al1 review recent findings that suggest the endothelial protein C receptor (EPCR), known for its pivotal role in mediating cytoprotection against coagulopathy, proinflammatory cytokines, and vascular permeability, may serve as a receptor for Plasmodium falciparum-infected red blood cells (IRBCs) in the brain.2 In the process, coagulation is allowed to proceed unchecked and contributes to the pathogenesis of cerebral malaria.3. © 2014 by The American Society of Hematology. Source

Zheng X.-L.,University of Calgary
Archives of Biochemistry and Biophysics | Year: 2014

Myocardin (MYOCD), a co-transcriptional activator of serum response factor (SRF), stimulates the expression of smooth muscle (SM) genes and inhibits the cell cycle. In addition to its roles in the development, MYOCD may be critically involved in the pathogenesis of proliferative vascular diseases. This review mainly focuses on how MYOCD activity is regulated and how it inhibits cell proliferation. © 2013 Elsevier Inc. All rights reserved. Source

Rodrigue N.,University of Calgary | Lartillot N.,University Claude Bernard Lyon 1
Bioinformatics | Year: 2014

Motivation: In recent years, there has been an increasing interest in the potential of codon substitution models for a variety of applications. However, the computational demands of these models have sometimes lead to the adoption of oversimplified assumptions, questionable statistical methods or a limited focus on small data sets.Results: Here, we offer a scalable, message-passing- interface-based Bayesian implementation of site-heterogeneous codon models in the mutation-selection framework. Our software jointly infers the global mutational parameters at the nucleotide level, the branch lengths of the tree and a Dirichlet process governing across-site variation at the amino acid level. We focus on an example estimation of the distribution of selection coefficients from an alignment of several hundred sequences of the influenza PB2 gene, and highlight the site-specific characterization enabled by such a modeling approach. Finally, we discuss future potential applications of the software for conducting evolutionary inferences. © 2013 The Author 2013. Published by Oxford University Press. Source

Wang Y.,University of Calgary
International Journal of Cognitive Informatics and Natural Intelligence | Year: 2014

Eyes as the unique organ possess intensively direct connections to the brain and dynamically perceptual accessibility to the mind. This paper analyzes the cognitive mechanisms of eyes not only as the sensory of vision, but also the browser of internal memory in thinking and perception. The browse function of eyes is created by abstract conditioning of the eye's tracking pathway for accessing internal memories, which enables eye movements to function as the driver of the perceptive thinking engine of the brain. The dual mechanisms of the eyes as both the external sensor of the brain and the internal browser of the mind are explained based on evidences and cognitive experiences in cognitive informatics, neuropsychology, cognitive science, and brain science. The finding on the experiment's internal browsing mechanism of eyes reveals a crucial role of eyes interacting with the brain for accessing internal memory and the cognitive knowledge base in thinking, perception, attention, consciousness, learning, memorization, and inference. Copyright © 2014, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Copyright © 2014, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Source

Background: The pathophysiology of delayed neurological deficits (DNDs) following aneurysmal subarachnoid hemorrhage (SAH) is complex, and is not limited to arterial narrowing (vasospasm) and classical ischemia. Thus, combined drug approaches, or therapies with multiple effects, may have the greatest potential for benefit. Statins are known to have pleiotropic vascular effects, some of which may interrupt the pathogenesis of DNDs. Based on promising preliminary reports, many clinicians routinely administer statins to prevent DNDs. Methods: A systematic review was performed to identify and summarize all animal research, observational studies, randomized controlled trials (RCTs) and meta-analyses which have evaluated the use of statins in the management of SAH. Results: Nine animal studies, nine observational (cohort and case-control) studies, six RCTs and three meta-analyses were identified. Animal studies have generally administered statin doses that, when adjusted for body weight, are 10-80 times larger than what is used in humans. Nevertheless, these models have consistently reported statins to reduce vasospasm and to demonstrate additional neuroprotective effects. However, observational studies have not revealed an association between statin-use and reduced DNDs or improved neurological outcomes. Results of RCTs have been inconsistent and limited by small sample size, but together suggest that statins may reduce DNDs, with no clear impact on mortality or neurological recovery. Optimal drug administration strategies (timing of initiation, most effective dose and duration) have not been clarified. Conclusions: The role of statins in the management of patients with SAH remains unclear. Although promising, statins should not, at this time, be considered standard care. © Springer-Verlag/Wien 2011. Source

Aguilera R.,University of Calgary
SPE Reservoir Evaluation and Engineering | Year: 2014

Core data from various North American basins with the support of limited amounts of data from other basins around the world have shown in the past that process speed or delivery speed (the ratio of permeability to porosity) provides a continuum between conventional, tight-, and shale-gas reservoirs (Aguilera 2010a). This work shows that the previous observation can be extended to tight-oil and shale-oil reservoirs. The link between the various hydrocarbon fluids is provided by the word "petroleum" in the "total petroleum system (TPS)," which encompasses liquid and gas hydrocarbons found in conventional, tight, and shale reservoirs. Results of the present study lead to distinctive flow units for each type of reservoir that can be linked empirically to gas and oil rates and, under favorable conditions, to production decline. To make the work tractable, the bulk of the data used in this paper has been extracted from published geologic and petroleum-engineering literature. The paper introduces an unrestricted/transient/interlinear transition flow period in a triple-porosity model for evaluating the rate performance of multistage-hydraulically-fractured (MSHF) tightoil reservoirs. Under ideal conditions, this flow period is recognized by a straight line with a slope of -1.0 on log-log coordinates. However, the slope can change (e.g., to -0.75), depending on reservoir characteristics, as shown with production data from the Cardium and Shaunavon formations in Canada. This interlinear flow period has not been reported previously in the literature because the standard assumption for MSHF reservoirs has been that of a pseudosteady- state transition between the linear flow periods. It is concluded that there is a significant practical potential in the use of process speed as part of the flow-unit characterization of unconventional petroleum reservoirs. There is also potential for the evaluation of production-decline rates by the use of the tripleporosity model presented in this study. Copyright © 2014 Society of Petroleum Engineers. Source

Acute graft-versus-host disease (GVHD) is a cause of substantial morbidity and mortality following allogeneic stem cell transplantation. Complete responses to steroid-based front-line treatment occur in 25-40% of patients, and results of second-line treatment are unsatisfactory. This review examines the biological effects of mesenchymal stromal cells (MSCs) in relation to GVHD and describes the clinical results of GVHD treatment with cultured MSCs and the proprietary cryopreserved MSCs known as remestemcel-L. Copyright © 2012 Prous Science, S.A.U. or its licensors. All rights reserved. Source

Wang Y.,University of Calgary
WSEAS Transactions on Computers | Year: 2014

Fuzzy semantics comprehension and fuzzy inference are two of the central abilities of human brains that play a crucial role in thinking, perception, and problem solving. A formal methodology for rigorously describing and manipulating fuzzy semantics and fuzzy concepts is sought for bridging the gap between humans and cognitive fuzzy systems. A mathematical model of fuzzy concepts is created based on concept algebra as the basic unit of fuzzy semantics for denoting languages entities in semantic analyses. The semantic operations of fuzzy modifiers and qualifiers on fuzzy concepts are introduced to deal with complex fuzzy concepts. On the basis the fuzzy semantic models, fuzzy causations and fuzzy causal inferences are formally elaborated by algebraic operations. The denotational mathematical structure of fuzzy semantics and fuzzy inferences not only explains the fuzzy nature of linguistic semantics and its comprehension, but also enables cognitive machines and fuzzy systems to mimic the human fuzzy inference mechanisms in cognitive informatics, cognitive linguistics, cognitive computing, and computational intelligence. Source

Lee D.V.,University of Calgary
Proceedings. Biological sciences / The Royal Society | Year: 2013

This study compares human walking and running, and places them within the context of other mammalian gaits. We use a collision-based approach to analyse the fundamental dynamics of the centre of mass (CoM) according to three angles derived from the instantaneous force and velocity vectors. These dimensionless angles permit comparisons across gait, species and size. The collision angle Φ, which is equivalent to the dimensionless mechanical cost of transport CoTmech, is found to be three times greater during running than walking of humans. This threefold difference is consistent with previous studies of walking versus trotting of quadrupeds, albeit tends to be greater in the gaits of humans and hopping bipeds than in quadrupeds. Plotting the collision angle Φ together with the angles of the CoM force vector Θ and velocity vector Λ results in the functional grouping of bipedal and quadrupedal gaits according to their CoM dynamics-walking, galloping and ambling are distinguished as separate gaits that employ collision reduction, whereas trotting, running and hopping employ little collision reduction and represent more of a continuum that is influenced by dimensionless speed. Comparable with quadrupedal mammals, collision fraction (the ratio of actual to potential collision) is 0.51 during walking and 0.89 during running, indicating substantial collision reduction during walking, but not running, of humans. Source

Hinnell C.,University of Calgary
The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques | Year: 2012

Sex differences in the risk factors, presentation and outcome of cerebral venous sinus thrombosis (CVST) are poorly defined, despite a discrepant prevalence between males and females. The proportion of patients on hormonal therapy who develop CVST varies widely. We describe the clinical features, risk factors and outcome by sex and by hormone-related risk factors among a large cohort of patients. We reviewed records of 108 consecutive patients with CVST at a tertiary hospital in Calgary between 1999 and 2009. Descriptive statistics were used for between group comparisons (men, women with hormone-related risk factors and women without hormone-related risk factors). Females made up 62% of patients, half of whom were on systemic hormonal therapy. Men and women without hormonal risk factors were older at onset. Oral contraceptive use was the major risk factor in women (45%) while concurrent mastoiditis was the most common predisposing factor in men (27%). Complications were frequent and overall mortality was 6%. Persisting deficits at discharge were more common in men (54% vs. 35% and 32%, p=0.036). There was a trend for women with hormone-related risk factors to have less residual focal neurologic deficit than the other groups (5% vs. 15% and 17%, p=0.051). There are differences between sexes in the presentation, risk factors and outcome of patients with CVST. Source

Thomas R.E.,University of Calgary
Cochrane database of systematic reviews (Online) | Year: 2010

BACKGROUND: Although the evidence to support influenza vaccination is poor, it is promoted by many health authorities. There is uncertainty about the effectiveness of interventions to increase influenza vaccination rates in those 60 years or older. OBJECTIVES: To assess effects of interventions to increase influenza vaccination rates in those 60 or older. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010, issue 3), containing the Cochrane Acute Respiratory Infections Group's Specialized Register, MEDLINE (January 1950 to July 2010), PubMed (January 1950 to July 2010), EMBASE (1980 to 2010 Week 28), AgeLine (1978 to July 2010), ERIC (1965 to July 2010) and CINAHL (1982 to July 2010). SELECTION CRITERIA: Randomized controlled trials (RCTs) to increase influenza vaccination rates in those aged 60 years and older, recording influenza vaccination status either through clinic records, billing data or local/national vaccination registers. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed study quality and extracted data. MAIN RESULTS: Forty-four RCTs were included. All included RCTs studied seniors in the community and in high-income countries. No RCTs of society-level interventions were included. Heterogeneity was marked and meta-analysis was limited. Only five RCTs were graded at low and six at moderate risk of bias. They included three of 13 personalized postcard interventions (all three with the 95% confidence interval (CI) above unity), two of the four home visit interventions (both with 95% CI above unity, but one a small study), three of the four reminder to physicians interventions (none with 95% CI above unity) and three of the four facilitator interventions (one with 95% CI above unity, and one P < 0.01). The other 33 RCTs were at high risk of bias and no recommendations for practice can be drawn. AUTHORS' CONCLUSIONS: Personalized postcards or phone calls are effective, and home visits, and facilitators, may be effective. Reminders to physicians are not. There is insufficient good evidence for other interventions. Source

Turner R.W.,University of Calgary
Channels (Austin, Tex.) | Year: 2011

Voltage gated calcium channels are key mediators of depolarization induced calcium entry into electrically excitable cells. There is increasing evidence that voltage gated calcium channels, like many other types of ionic channels, do not operate in isolation, but instead forms signaling complexes with signaling molecules, G protein coupled receptors, and other types of ion channels. Furthermore, there appears to be bidirectional signaling within these protein complexes, thus allowing not only for efficient translation of calcium signals into cellular responses, but also for tight control of calcium entry per se. In this review, we will focus predominantly on signaling complexes between G protein-coupled receptors and high voltage activated calcium channels, and on complexes of voltage-gated calcium channels and members of the potassium channel superfamily. Source

Hardin J.,University of Calgary
Skin therapy letter | Year: 2010

Solid organ transplant recipients (OTRs) have an increased incidence of skin cancer, resulting in significant morbidity and mortality post-transplantation. Chemoprevention strategies are focused on reducing and delaying the development of skin cancer in these patients. Although systemic retinoids are widely used in OTRs, few randomized controlled trials have been performed. Limited data suggest that acitretin may have a beneficial role in high-risk OTRs. Since rebound flares occur upon discontinuation of retinoids, chemoprevention should be viewed as a lifelong therapy. Further studies are required to establish the efficacy and long-term safety of systemic retinoids as chemopreventive agents for high-risk transplant recipients. Source

Ishii H.S.,University of Toyama | Harder L.D.,University of Calgary
Journal of Ecology | Year: 2012

1. Flowering-time differences within and among protandrous, hermaphroditic plants shift the floral sex ratio from male- to female-dominated during a population's flowering season. This dynamic should induce negative frequency-dependent selection favouring relatively greater investment of resources and time in female function by early flowers and early-flowering plants than by late flowers and late-flowering individuals. In contrast, selection for floral integration to facilitate pollen export and import should limit floral variation. 2.We assessed these contrasting expectations for the protandrous Delphinium glaucum by considering the relation of variation and covariation in the lengths of perianth segments, anther and ovule number, and male- and female-phase duration for flowers at three positions within inflorescences to the first flowering date, mean gender and size of 34 plants. 3.Reproductive phenotypes varied among and within plants in association with a shift in population floral sex ratio from male- to female-biased, but not with plant size. Early-flowering plants had female-biased phenotypic gender and smaller flowers with fewer anthers per ovule and shorter male phases than late-flowering plants. Within individuals, earlier (lower) flowers were larger with higher female effort, in terms of both the relative production of ovules and anthers and the relative durations of female and male phases, than later (upper) flowers. Overall, these results are more consistent with the expectations of negative frequency-dependent selection than with proximate resource allocation. 4.Correlations among floral traits indicated significant floral integration. However, these correlations weakened from lower to upper flowers, suggesting that the patterns of intra-individual variation limit the extent of integration. 5.Synthesis. Reproductive phenotypes that incorporate systematic among-flower variation and vary consistently among individuals with flowering time, such as those exhibited by D. glaucum, may be typical of dichogamous species with multi-flowered inflorescences. Such diversity within and among plants should result from a combination of density-dependent selection against simultaneous flowering of individuals and frequency-dependent selection favouring emphasis on the least common sex role during specific stages of the flowering season, both facilitated by the positive assortative mating that accompanies asynchronous flowering among individuals. Delphinium glaucum exhibits systematic variation in flower size and female and male effort, both within and among plants. These variation patterns are consistent with shifting selection on sex function during the flowering season caused as the population floral sex ratio changes from male- to female-biased, which may limit correlations among floral traits that facilitate interactions with pollinators. © 2012 The Authors. Journal of Ecology © 2012 British Ecological Society. Source

Bierman A.,University of Calgary
Journals of Gerontology - Series B Psychological Sciences and Social Sciences | Year: 2011

Objectives. This study examines how mastery mediates and moderates the relationship between pain and depression among older adults, as well as the extent to which these processes differ by the timing of pain in late life, while utilizing statistical methods that comprehensively control for time-stable confounds. Methods. Data are derived from multiple observations of adults aged 65 years and older in the Washington, DC, metropolitan area over a 4-year period. Fixed effects models are used to control for time-stable influences. Results. With all time-stable influences controlled, pain is positively related to symptoms of depression, although this relationship is substantially reduced in comparison with a model in which all time-stable confounds are not held constant. Mastery does not mediate this relationship because pain is not significantly related to mastery once time-stable factors are taken into account. Mastery buffers the relationship between pain and depression, but only for elders later in late life. Discussion. This study suggests that a synthesis of stress process and life course perspectives is critical for understanding how pain influences depression in late life. However, research that does not comprehensively control for time-stable factors may overestimate the consequences of pain for older adults. © The Author 2011. Source

Thomas R.E.,University of Calgary
The Cochrane database of systematic reviews | Year: 2013

Helping young people to avoid starting smoking is a widely endorsed public health goal, and schools provide a route to communicate with nearly all young people. School-based interventions have been delivered for close to 40 years. The primary aim of this review was to determine whether school smoking interventions prevent youth from starting smoking. Our secondary objective was to determine which interventions were most effective. This included evaluating the effects of theoretical approaches; additional booster sessions; programme deliverers; gender effect was detected at one year or less. The combined social competence and social influences interventions showed a significant effect at one year and at longest follow-up. Studies that deployed a social influences programme showed no overall effect at any time point; multimodal interventions and those with an information-only approach were similarly ineffective.Studies reporting Change in Smoking Behaviour over time did not show an overall effect, but at an intervention level there were positive findings for social competence and combined social competence and social influences interventions. Source

Tsang R.Y.,University of Calgary | Tsang R.Y.,University of California at Los Angeles | Finn R.S.,University of California at Los Angeles
British Journal of Cancer | Year: 2012

The use of trastuzumab, a monoclonal antibody that targets the human epidermal growth factor receptor 2 (HER2) alteration present in 25 to 30% of breast cancers, has been associated with improved survival outcomes in both the adjuvant and metastatic settings. However, despite the robust clinical efficacy of trastuzumab in HER2-positive metastatic breast cancer (MBC), primary and secondary resistance remains a clinical challenge. Although lapatinib has demonstrated modest activity in this setting, trials reported to date have yet to demonstrate improvements in overall survival with its use. Novel therapeutic strategies to circumvent trastuzumab resistance are warranted, and agents targeting the HER, vascular endothelial growth factor, heat shock protein 90, phosphoinositide 3 kinase/Akt/mammalian target of rapamycin, and insulin-like growth factor-1 receptor pathways represent rational approaches in the management of HER2-positive disease. In this review, early-phase and emerging trial data surrounding the use of these promising agents in HER2-positive MBC will be discussed. © 2012 Cancer Research UK All rights reserved. Source

Belostotski L.,University of Calgary
IEEE Transactions on Microwave Theory and Techniques | Year: 2011

The inequality relating Fmin and Lange invariant N for any noisy linear two-port network has been known since the 1980s. However, the applicability of this inequality to MOSFETs is not discussed in the literature, and thus, this inequality is not normally treated in analyses and designs of circuits based on MOSFETs. This work shows that by using N, the number of noise parameters required to model high-frequency noise of intrinsic MOSFETs can be reduced by one. This reduction in the noise parameters simplifies the noise correlation matrices, which leads to simpler noise factor expressions. A new set of noise correlation matrices and noise factor expressions is presented. These are expected to ease circuit optimizations of low-noise amplifiers and other circuits based on intrinsic MOSFET models. © 2011 IEEE. Source

Federico S.,University of Calgary
Mathematics and Mechanics of Solids | Year: 2010

The deformation gradient admits a multiplicative decomposition into a purely volumetric component and a purely distortional component. For a hyperelastic material, based on this decomposition, the elastic strain energy potential, the stress, and the elasticity tensor can be expressed in general as a function of both the volumetric deformation and the distortional deformation. However, the volumetric-distortional decomposition of deformation has often been employed in a fully decoupled form of the elastic strain energy potential, which is expressed as the sum of a term depending solely on the volumetric deformation and a term depending solely on the distortional deformation. This work has three main objectives. First, to derive the elasticity tensor in the general (non-decoupled) case, in its material, spatial, and linear forms; this is achieved by extensive use of fourth-order tensor algebra, and in particular of the properties of the so-called spherical operator, which is largely used, but very seldom given the dignity of being assigned a symbol and a name, in the literature. Second, to show that a fully decoupled potential gives rise to an elasticity tensor which may be inconsistent with its linearized counterpart, as some components of the linear elasticity tensor in general do not have a corresponding term in nonlinear decoupled elasticity tensor. Third, to obtain the conditions under which a purely hydrostatic stress causes a purely volumetric deformation, by means of the developed theory; the results show that this condition is satisfied if and only if the elastic potential is fully decoupled. While the whole approach is completely independent of the material symmetry, the cases of isotropy and transverse isotropy are shown as an example. © 2010 The Author(s). Source

Sangouard N.,University of Geneva | Sangouard N.,CNRS Materials and Quantum Phenomena Laboratory | Simon C.,University of Geneva | Simon C.,University of Calgary | And 4 more authors.
Reviews of Modern Physics | Year: 2011

The distribution of quantum states over long distances is limited by photon loss. Straightforward amplification as in classical telecommunications is not an option in quantum communication because of the no-cloning theorem. This problem could be overcome by implementing quantum repeater protocols, which create long-distance entanglement from shorter-distance entanglement via entanglement swapping. Such protocols require the capacity to create entanglement in a heralded fashion, to store it in quantum memories, and to swap it. One attractive general strategy for realizing quantum repeaters is based on the use of atomic ensembles as quantum memories, in combination with linear optical techniques and photon counting to perform all required operations. Here the theoretical and experimental status quo of this very active field are reviewed. The potentials of different approaches are compared quantitatively, with a focus on the most immediate goal of outperforming the direct transmission of photons. © 2011 American Physical Society. Source

Howlett J.G.,University of Calgary
Canadian Journal of Cardiology | Year: 2014

β-adrenergic blocking agents, a pharmacologically diverse class of cardiovascular medications, are recommended as first-line treatment for patients with hypertension and concomitant structural heart disease, and for angina and heart failure. Many within-class differences exist, from pharmacokinetics and pharmacodynamics to ancillary effects, such as intrinsic sympathomimetic activity, antiarrhythmic activity, α-1 adrenergic receptor blockade affinity, and direct vasodilation. Nebivolol is a third-generation, β1 selective, long acting β-blocker, which causes direct vasodilation via endothelium-dependent nitric oxide stimulation. The vasodilatory actions of nebivolol might result in clinical effects with some distinct properties. Differences from other β-blockers might include improvement of endothelial function, enhancement of forward flow in muscular resistance arteries, maintenance of exercise tolerance, and overall improved tolerability, side effect profile, and adherence. Nebivolol has been shown to be a clinically effective β-blocker for treatment as initial or add-on therapy for systemic hypertension, as an antianginal agent, and as therapy for patients with heart failure. These properties position nebivolol as a treatment option for patients with hypertension and/or structural heart disease, although its precise role in the therapeutic armamentarium remains to be clarified. © 2014 Canadian Cardiovascular Society. Source

Paton B.I.,University of Calgary
Journal of Nursing Education | Year: 2010

Significant research has been conducted and disseminated on preceptorship as an essential component in teaching and evaluating student learning in the final clinical practicum. The preceptorship triad-formally defined as an equilateral relationship among a nurse preceptor, faculty member, and undergraduate nursing student-overlooks the contextual challenges preceptors encounter. Preceptors develop relationships in the clinical setting to enhance teaching, and more importantly, to ensure student practice reflects the depth of clinical reasoning and skill acquisition necessary for safe and competent practice. Using descriptive surveys and qualitative focus groups, a research collaborative among academia, practice, and professional regulating bodies was established in southern Alberta, Canada, to research the types of knowledge nurses acquire and integrate to successfully assess, evaluate, and teach undergraduate nursing students in the clinical environment. This article describes the research findings and highlights the professional practice knowledge of nurse preceptors. © SLACK Incorporated. Source

Ouyed R.,University of Calgary
Monthly Notices of the Royal Astronomical Society | Year: 2013

The genesis and chemical patterns of the metal-poor stars in the galactic halo remain an open question. Current models do not seem to give a satisfactory explanation for the observed abundances of lithium in the galactic metal-poor stars and the existence of carbon-enhanced metal-poor (CEMP) and nitrogen-enhanced metal-poor (NEMP) stars. In order to deal with some of these theoretical issues, we suggest an alternative explanation, where some of the Pop III supernovae (SNe) are followed by the detonation of their neutron stars [quark-novae (QNe)]. In QNe occurring a few days to a few weeks following the preceding SN explosion, the neutron-rich relativistic QN ejecta leads to spallation of 56Ni processed in the ejecta of the precedingSNexplosion and thus to 'iron/metal impoverishment' of the primordial gas swept by the combined SN+QN ejecta. We show that the generation of stars formed from fragmentation of pristine clouds swept up by the combined SN+QN ejecta acquires a metallicity with-7.5< [Fe/H] < -1.5 for dual explosions with 2 < tdelay (d) < 30. Spallation leads to the depletion of 56Ni and formation of sub-Ni elements such as Ti, V, Cr and Mn providing a reasonable account of the trends observed in galactic halo metal-poor stars. CEMP stars form in dual explosions with short delays (tdelay < 5 d). These lead to important destruction of 56Ni (and thus to a drastic reduction of the amount of Fe in the swept-up cloud) while preserving the carbon processed in the outer layers of the SN ejecta. Lithium is produced from the interaction of the neutron-rich QN ejecta with the outer (oxygen-rich) layers of the SN ejecta. A lithium plateau with 2 < A(Li) < 2.4 can be produced in our model as well as a corresponding 6Li plateau with 6Li/7Li < 0.3. ©2012 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

Pillai D.R.,University of Calgary
Malaria journal | Year: 2014

BACKGROUND: Bangladesh is a malaria hypo-endemic country sharing borders with India and Myanmar. Artemisinin combination therapy (ACT) remains successful in Bangladesh. An increase of artemisinin-resistant malaria parasites on the Thai-Cambodia and Thai-Myanmar borders is worrisome. K13 propeller gene (PF3D7_1343700 or PF13_0238) mutations have been linked to both in vitro artemisinin resistance and in vivo slow parasite clearance rates. This group undertook to evaluate if mutations seen in Cambodia have emerged in Bangladesh where ACT use is now standard for a decade.METHODS: Samples were obtained from Plasmodium falciparum-infected malaria patients from Upazila health complexes (UHC) between 2009 and 2013 in seven endemic districts of Bangladesh. These districts included Khagrachari (Matiranga UHC), Rangamati (Rajasthali UHC), Cox's Bazar (Ramu and Ukhia UHC), Bandarban (Lama UHC), Mymensingh (Haluaghat UHC), Netrokona (Durgapur and Kalmakanda UHC), and Moulvibazar (Sreemangal and Kamalganj UHC).RESULTS: Out of 296 microscopically positive P. falciparum samples, 271 (91.6%) were confirmed as mono-infections by both real-time PCR and nested PCR. The K13 propeller gene from 253 (93.4%) samples was sequenced bi-directionally. One non-synonymous mutation (A578S) was found in Bangladeshi clinical isolates. The A578S mutation was confirmed and lies adjacent to the C580Y mutation, the major mutation causing delayed parasite clearance in Cambodia. Based on computational modeling A578S should have a significant effect on tertiary structure of the protein.CONCLUSION: The data suggest that P. falciparum in Bangladesh remains free of the C580Y mutation linked to delayed parasite clearance. However, the mutation A578S is present and based on structural analysis could affect K13 gene function. Further in vivo clinical studies are required to validate the effect of this mutation. Source

Simon C.,University of Calgary | Polzik E.S.,Copenhagen University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

Weak measurements in combination with postselection can give rise to a striking amplification effect (related to a large "weak value"). We show that this effect can be understood by viewing the initial state of the pointer as the ground state of a fictional harmonic oscillator. This perspective clarifies the relationship between the weak-value regime and other measurement techniques and inspires a proposal to implement fully quantum weak-value measurements combining photons and atomic ensembles. © 2011 American Physical Society. Source

ter Keurs H.E.D.J.,University of Calgary
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2012

The hallmarks of the normal heartbeat are both rapid onset of contraction and rapid relaxation as well as an inotropic response to both increased end-diastolic volume and increased heart rate. At the microscopic level, Ca 2+ plays a crucial role in normal cardiac contraction. This paper reviews the cycle of Ca 2+ fluxes during the normal heartbeat, which underlie the coupling between excitation and contraction and permit a highly synchronized action of cardiac sarcomeres. Length dependence of the response of the regulatory sarcomeric proteins mediates the Frank-Starling Law of the heart. However, Ca 2+ transport may go astray in heart disease such as in congestive heart failure, and both jeopardize systole and diastole and triggering arrhythmias. The interaction between weak and strong segments in non uniform cardiac muscle allows partial preservation of force of contraction but may further lead to mechanoelectric feedback or reverse excitation-contraction coupling mediating an early diastolic Ca 2+ transient caused by the rapid force decrease during the relaxation phase. These rapid force changes in non uniform muscle may cause arrhythmogenic Ca 2+ waves to propagate by the activation of neighboring sarcoplasmic reticulum by diffusing Ca 2+ ions. © 2012 the American Physiological Society. Source

Wright Jr. J.R.,University of Calgary
Archives of Pathology and Laboratory Medicine | Year: 2014

Context. - Malcolm B. Dockerty and Lewis B. Woolner, 2 preeminent mid-20th-century surgical pathologists, spent their entire careers at the Mayo Clinic. Both were raised in poverty on potato farms only 49 miles apart in Canada's smallest province (Prince Edward Island); both were educated in 1-room schools and graduated as gold medalists from Prince Edward Island's only college and then from Maritime Canada's only medical school; both then trained at the Mayo Clinic. Objective. - To explore the lives and accomplishments of these 2 important surgical pathologists. Design. - Standard historiographic methods were used to explore primary and secondary historical sources. Results. - Both became world-renowned general surgical pathologists, one developing subspecialty expertise in gynecologic pathology and the other in cytopathology, pulmonary pathology, and thyroid/parathyroid pathology. Both were prolific authors with h-indices higher than 40, and between them, they published more than 750 peerreviewed papers and book chapters. As educators, they trained hundreds of pathology and surgery residents/ fellows who disseminated their knowledge around the world. Both were fascinated by poetry from childhood and could quote the classics from memory. One wrote poetry throughout his entire life and even used it to teach pathology and serve as his memoir; the other strongly preferred the classics and in jest called his colleague "a (minor) poet." Both received postretirement honorary doctorates from their alma maters. Dockerty died in 1987; Woolner celebrates his 100th birthday on November 17, 2013. Conclusion. - Every pathologist should know of these 2 pioneering surgical pathologists. Source

Hanly P.J.,Sleep Center | Ahmed S.B.,University of Calgary
Chest | Year: 2014

The prevalence of chronic kidney disease (CKD) is increasing, which presents challenges for both patients and health-care budgets. Although this phenomenon has been attributed to the growth in diabetes, hypertension, and obesity, sleep apnea and nocturnal hypoxemia may also contribute to the pathogenesis of CKD and its progression to kidney failure. Two pathophysiologic mechanisms responsible for CKD are glomerular hyperfi ltration and chronic intrarenal hypoxia, resulting in tubulointerstitial injury, the fi nal common pathway to endstage kidney disease (ESKD). Multiple descriptive studies have demonstrated an association between CKD and sleep apnea. Although sleep apnea is common in patients with CKD and associated with signifi cant nocturnal hypoxemia, it is often relatively free of sleep-related symptoms, making it diffi cult to detect without objective nocturnal monitoring. Nevertheless, sleep apnea and nocturnal hypoxemia have been associated with loss of kidney function and kidney injury, suggesting that they contribute to the pathogenesis of continued deterioration in kidney function. There are several pathways through which sleep apnea may achieve this, including a direct eff ect of intrarenal hypoxia and activation of the systemic and renal reninangiotensin system. Further research is required to better understand these relationships and determine whether specifi c interventions in patients with sleep apnea have an impact on clinical outcomes, such as reducing the prevalence of CKD and delaying its progression to ESKD. © 2014 AMERICAN COLLEGE OF CHEST PHYSICIANS. Source

Villarreal-Barajas J.E.,University of Calgary
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2014

The objective of this study is to evaluate the suitability of recently introduced radiochromic film EBT3 for clinical dosimetry in the kilovoltage (kV) range. For this purpose, a kV X-ray irradiator, X RAD 320ix in the range 70 to 300 kVp, a clinical 60Co source, a 6 MV and an 18 MV X-ray clinical beam from a Varian linear accelerator were calibrated following AAPM dosimetry protocols. EBT3 films from two different EBT3 batches were placed side-by-side on the surface of a water phantom; doses from 0.5 to 4 Gy were delivered. Similarly, irradiations were performed for 60Co and 6 and 18 MV beams in a water equivalent phantom. Films were reproducibly placed at the center of a flatbed scanner and 48-bit RGB scans were obtained both pre- and postirradiations. Net optical density (netOD) and response for a given radiation quality relative to 60Co was determined for each EBT3 film. The netOD of the red color showed reproducible response (within 1%) for both batches when irradiated using the 60Co source. For a given dose of 1 Gy of kVp X-ray, the response relative to 60Co using the three color channels (red, green, and blue) decreases with decrease in kVp, reaching a maximum underresponse of ~ 20% for the 70 kVp. A significant underresponse of ~ 5% was observed at 300kVp. Responses of MV X-ray beams with respect to 60Co at the 1 Gy dose level showed no statistically significant difference. A relatively small difference in the response was observed between the two EBT3 batches used in this study in the kV X-ray range. Source

Xue P.,Nanjing Southeast University | Sanders B.C.,University of Calgary
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We consider two independent quantum walks on separate lines augmented by partial or full swapping of coins after each step. For classical random walks, swapping or not swapping coins makes little difference to the random-walk characteristics, but we show that quantum walks with partial swapping of coins have complicated yet elegant interwalker correlations. Specifically we study the joint position distribution of the reduced two-walker state after tracing out the coins and analyze total, classical, and quantum correlations in terms of mutual information, quantum mutual information, and measurement-induced disturbance. Our analysis shows intriguing quantum features without classical analogs. © 2012 American Physical Society. Source

Belostotski L.,University of Calgary
IEEE Transactions on Microwave Theory and Techniques | Year: 2011

Uncertainties in noise-figure and noise-parameter measurements depend to a large degree on the accuracy with which noise sources are calibrated. In some cases, the uncertainties are similar to measured quantities. This paper discusses a method for calibration of RF and microwave noise sources against a reference noise source. This method takes into account noise parameters of the receiver used for noise power measurements and includes temperature corrections to account for both drifts in the ambient temperature and heat transfer between the receiver and noise sources. Experimental results demonstrate the feasibility of the proposed method. As estimated with a Monte Carlo analysis, a 2σ uncertainty of 0.046 dB for a 5-dB excess-noise-ratio (ENR) noise source is obtained with the proposed method. This uncertainty is approximately one third of ENR uncertainties reported for commercial noise sources. © 2010 IEEE. Source

Habib A.,University of Calgary
Environmental Values | Year: 2013

Philosophers often understand environmental sustainability as a duty of distributive justice between the generations of the earth. Since every generation is equally entitled to the bounty of the natural environment (the thinking goes) every generation should have a fair share of that bounty. But since generations precede each other in time, it is the duty of earlier generations to ensure that later generations receive their fair share. Acting sustainably is the way of meeting this duty, since sustainable practices are those that (ideally) preserve the environment for the future. But what is a 'fair' share of something as complex, varied and dynamic as 'the environment'? How are we to value nature for the purposes of measuring 'shares' of it? I think the answer to these questions lies in the difference between sharing something by parts, like a pie, and sharing something by turns, like a bicycle. The generations share the earth by turns, not by parts, and so questions about fairness of shares are questions about turns, not parts. We need to ask what constitutes a 'fair turn' with the earth, and for that question we don't necessarily need to be able to commensurate the various parts of nature, just as we don't need to know the relative value of the parts of a bicycle to say what constitutes a fair turn with it. © 2013 The White Horse Press. Source

Al-Saleh M.H.,Jordan University of Science and Technology | Saadeh W.H.,Jordan University of Science and Technology | Sundararaj U.,University of Calgary
Carbon | Year: 2013

The microstructure, electromagnetic interference (EMI) shielding effectiveness (SE), DC electrical conductivity, AC electrical conductivity and complex permittivity of nanostructured polymeric materials filled with three different carbon nanofillers of different structures and intrinsic electrical properties were investigated. The nanofillers were multiwall carbon nanotubes (MWCNT), carbon nanofibers (CNF) and high structure carbon black (HS-CB) nanoparticles and the polymer was acrylonitrile-butadiene-styrene (ABS). In addition, the EMI SE mechanisms and the relation between the AC electrical conductivity in the X-band frequency range and the DC electrical conductivity were studied. The nanocomposites were fabricated by solution mixing and characterized by uniform dispersion of the nanofillers within the polymer matrix. It was found that, at the same nanofiller loading, the EMI SE, permittivity and electrical conductivity of the nanocomposites decreased in the following order: MWCNT > CNF > CB. MWCNT based nanocomposites exhibited the lowest electrical percolation threshold and the highest EMI SE owning to the higher aspect ratio and electrical conductivity of MWCNT compared to CNF and HS-CB. The AC conductivity in the X-band frequency range was found to be independent of frequency. © 2013 Elsevier Ltd. All rights reserved. Source

Barnieh L.,University of Calgary
Clinical journal of the American Society of Nephrology : CJASN | Year: 2012

The acceptability of financial incentives for organ donation is contentious. This study sought to determine (1) the acceptability of expense reimbursement or financial incentives by the general public, health professionals involved with organ donation and transplantation, and those with or affected by kidney disease and (2) for the public, whether financial incentives would alter their willingness to consider donation. Web-based survey administered to members of the Canadian public, health professionals, and people with or affected by kidney disease asking questions regarding acceptability of strategies to increase living and deceased kidney donation and willingness to donate a kidney under various financial incentives. Responses were collected from 2004 members of the Canadian public October 11-18, 2011; responses from health professionals (n=339) and people with or affected by kidney disease (n=268) were collected during a 4-week period commencing October 11, 2011. Acceptability of one or more financial incentives to increase deceased and living donation was noted in >70% and 40% of all groups, respectively. Support for monetary payment for living donors was 45%, 14%, and 27% for the public, health professionals, and people with or affected by kidney disease, respectively. Overall, reimbursement of funeral expenses for deceased donors and a tax break for living donors were the most acceptable. The general public views regulated financial incentives for living and deceased donation to be acceptable. Future research needs to examine the impact of financial incentives on rates of deceased and living donors. Source

Anderson T.J.,University of Calgary | Phillips S.A.,University of Illinois at Chicago
Progress in Cardiovascular Diseases | Year: 2015

The endothelium plays a crucial role in the regulation of vascular homeostasis. Our understanding of its role in health and disease has increased dramatically since the pivotal discovery of nitric oxide more than 30. years ago. Clinical researchers utilized emerging technologies to study the vasodilator properties of the endothelium in both the coronary and peripheral circulation. Early studies established the methodologies and were able to demonstrate attenuated endothelium-dependent vasodilation in response to atherosclerosis and its risk factors. A variety of interventions can modulate endothelial function. More recent studies have established that some of these measures are independent predictors of cardiovascular outcomes. As such, peripheral measures of endothelial function are now established surrogate markers of vascular risk and have become important markers for clinical research. In this review, we will discuss a variety of measures of peripheral artery function to assess both conduit and resistance vessel function in humans. © 2014 Elsevier Inc. Source

Hersikorn B.D.,University of Saskatchewan | Smits J.E.G.,University of Calgary
Environmental Pollution | Year: 2011

The wet landscape approach to oil sands tailings reclamation in the Athabasca Oil Sands region involves creating wetlands from fluid tailings in mined-out pits. We measured time to metamorphosis, thyroid hormone status, and detoxification enzyme (EROD) induction in Wood frog (Lithobates sylvaticus) tadpoles raised on reclaimed oil sands wetlands of different ages [young (≤7 yr) vs. old (>7 yr)] and compared data with tadpoles raised on reference (control) wetlands. Metamorphosis was delayed or never occurred in tadpoles raised in young tailings; those exposed to older tailings developed similarly to those in reference wetlands. Thyroid hormone disruption likely played an important role in the metamorphosis delay as the T3:T4 ratio was lowest in tadpoles raised in young, tailings-affected wetlands. Our findings suggest tailings wetlands become less toxic with age, and that these amphibians will be able to complete their life cycle in tailing wetlands that have sufficiently detoxified with age. © 2010 Elsevier Ltd. All rights reserved. Source

Parnell J.A.,Mount Royal College, Calgary | Reimer R.A.,University of Calgary
British Journal of Nutrition | Year: 2012

There is a growing interest in modulating gut microbiota with diet in the context of obesity. The purpose of the present study was to evaluate the dose-dependent effects of prebiotics (inulin and oligofructose) on gut satiety hormones, energy expenditure, gastric emptying and gut microbiota. Male lean and obese JCR:LA-cp rats were randomised to either of the following: lean 0 % fibre (LC), lean 10 % fibre (LF), lean 20 % fibre (LHF), obese 0 % fibre (OC), obese 10 % fibre (OF) or obese 20 % fibre (OHF). Body composition, gastric emptying, energy expenditure, plasma satiety hormone concentrations and gut microbiota (using quantitative PCR) were measured. Caecal proglucagon and peptide YY mRNA levels were up-regulated 2-fold in the LF, OF and OHF groups and 3-fold in the LHF group. Ghrelin O-acyltransferase mRNA levels were higher in obese v. lean rats and decreased in the OHF group. Plasma ghrelin response was attenuated in the LHF group. Microbial species measured in the Bacteroidetes division decreased, whereas those in the Firmicutes increased in obese v. lean rats and improved with prebiotic intake. Bifidobacterium and Lactobacillus increased in the OHF v. OC group. Bacteroides and total bacteria negatively correlated with percentage of body fat and body weight. Enterobacteriaceae increased in conjunction with glucose area under the curve (AUC) and glucagon-like peptide-1 AUC. Bacteroides and total bacteria correlated positively with ghrelin AUC yet negatively with insulin AUC and energy intake (P < 005). Several of the mechanisms through which prebiotics act (food intake, satiety hormones and alterations in gut microbiota) are regulated in a dose-dependent manner. The combined effects of prebiotics may have therapeutic potential for obesity. © The Authors 2011. Source

Sarnat H.B.,University of Calgary
Cell and Tissue Research | Year: 2015

Histological descriptions of morphogenesis in human fetal brain and in malformations and tumours can now be supplemented by the timing and sequence of the maturation of individual neurons. In human neuropathology, this is principally achieved by immunocytochemical reactivities used as maturational markers of neuronal properties denoted by molecules and cell products. Cytological markers can appear early and then regress, often being replaced by more mature molecules, or might not exhibit the onset of immunoreactivity until a certain stage of neuronal differentiation is achieved, some early, others intermediate and some late during the maturational process. Inter-specific differences occur in some structures of the brain. The classification of markers of neuronal maturation can be based, in addition to those mentioned above, on several criteria: cytological localisation, water solubility, biochemical nature of the antigen, specificity and various technical factors. The most useful immunocytochemical markers of neuronal maturation in human neuropathology are NeuN, synaptophysin, calretinin and other calcium-binding molecules, various microtubule-associated proteins and chromogranins. Non-antibody histochemical stains that denote maturational processes include luxol fast blue for myelination, acridine orange fluorochrome for nucleic acids, mitochondrial respiratory chain enzymes and argentophilic impregnations. Neural crest derivatives of the peripheral nervous system, including chromaffin and neuroendocrine cells, have special features that are shared and others that differ greatly between lineages. Other techniques used in human diagnostic neuropathology, particularly as applied to tumours, include chromosomal and genetic analyses, the mTOR signalling pathway, BRAF V600E and other tumour-suppressor gene products, transcription products of developmental genes and the proliferation index of the tumour cells and of mitotic neuroepithelial cells. © 2014, Springer-Verlag Berlin Heidelberg. Source

Hollis A.,University of Calgary
Journal of Law, Medicine and Ethics | Year: 2015

Antibiotics may be thought of as a common pool resource that can be depleted over time; the economics of this problem are relatively well known. The importance of antibiotics to human health means that limiting access through privatization is undesirable. Therefore, other solutions to prevent overuse are essential - stewardship programs, and for non-human use, taxation, all within the context of an international agreement. To solve problems of access while offering adequate rewards for innovation, a key tool is delinking prices from payment to innovators. © 2015 American Society of Law, Medicine & Ethics, Inc. Source

Mckay D.M.,University of Calgary
Parasite Immunology | Year: 2015

Summary: Successful endoparasites of mammals must outwit the sophisticated immune systems of their hosts that have evolved to detect and destroy/eradicate them. Many species of helminth parasite can directly or indirectly manipulate host immunity: helminth-derived molecules can suppress or skew activity of many immune cell phenotypes, and mobilization of regulatory cells in response to infection can inhibit immune cell activation. Moreover, many investigations, principally in laboratory-based rodent-helminth systems, demonstrate that infection with helminths (trematode, cestode or nematode) can ameliorate the severity of concomitant disease that model diabetes, inflammatory bowel disease and multiple sclerosis. Ongoing analyses in these model systems may uncover novel approaches to the management and cure of inflammatory diseases that are major global health issues. However, the potential of environmentally or experimentally (i.e. 'therapeutically') acquired infection with helminth parasites to exaggerate the severity immunopathologies in the host should not be overlooked. Here, examples of infection with helminth parasites exacerbating concomitant disease and commentary on possible adverse effects of helminth therapy are provided - the intent is not to undermine the development of helminth therapy, but to illustrate caveats that may need to be considered should helminth therapy be utilized as a treatment for inflammatory disease. © 2014 John Wiley & Sons Ltd. Source

Sharkey K.A.,University of Calgary
Journal of Clinical Investigation | Year: 2015

Enteric glia are important components of the enteric nervous system (ENS) and also form an extensive network in the mucosa of the gastrointestinal (GI) tract. Initially regarded as passive support cells, it is now clear that they are actively involved as cellular integrators in the control of motility and epithelial barrier function. Enteric glia form a cellular and molecular bridge between enteric nerves, enteroendocrine cells, immune cells, and epithelial cells, depending on their location. This Review highlights the role of enteric glia in GI motility disorders and in barrier and defense functions of the gut, notably in states of inflammation. It also discusses the involvement of enteric glia in neurological diseases that involve the GI tract. Source

Mahler M.,INOVA Diagnostics Inc. | Fritzler M.J.,University of Calgary
Clinical and Developmental Immunology | Year: 2012

Antinuclear antibodies (ANAs) are a serological hallmark in the diagnosis of systemic autoimmune rheumatic diseases (SARD). The indirect immunofluorescence (IIF) assay on HEp-2 cells is a commonly used test for the detection of ANA and has been recently recommended as the screening test of choice by a task force of the American College of Rheumatology. However, up to 20% of apparently healthy individuals (HI) have been reported to have a positive IIF ANA test, primarily related to autoantibodies that target the dense fine speckles 70 (DFS70) antigen. Even more important, the DFS IIF pattern has been reported in up to 33% of ANA positive HI, but not in ANA positive SARD sera. Since the intended use of the ANA HEp-2 test is to aid in the diagnosis and classification of SARD, the detection and reporting of anti-DFS70 antibodies and their associated pattern (DFS) as a positive test significantly reduce the specificity and the positive likelihood of the ANA test. This has significant implications for medical management and diagnostic algorithms involving the detection of ANA. Recently, a novel immunoadsorption method has been developed that specifically blocks anti-DFS70 antibodies and, therefore, significantly increases the specificity of the ANA test for SARD. This immunoadsorption method has the potential to overcome a significant limitation of the ANA HEp-2 assay. The present paper summarizes the current knowledge about anti-DFS70 antibodies and their clinical impact on ANA testing. © 2012 Michael Mahler and Marvin J. Fritzler. Source

Penuela S.,University of Western Ontario | Simek J.,University of Western Ontario | Thompson R.J.,University of Calgary
FEBS Letters | Year: 2014

The large-pore channels formed by the pannexin family of proteins have been implicated in many physiological and pathophysiological functions, mainly through their ATP release function. However, a tight regulation of channel opening is necessary to modulate their function in vivo. Post-translational modifications have been postulated as some of the regulating mechanisms for Panx1, while Panx2 and Panx3 have not been as well characterized. Positive regulators include caspase cleavage to open Panx1 channels in apoptotic cells, and activation by Src family kinases via ionotropic receptors in neurons and macrophages. S-nitrosylation of cysteines has been shown to both inhibit and activate the Panx1 channel in different cell types. All three pannexins are N-glycosylated but to different levels of modification. Their diverse glycosylation appears to regulate cellular localization, intermixing, and may restrict their ability to function as inter-cellular channels. It is clear that our understanding of pannexin post-translational modification and their role in channel function regulation is still in its infancy even a decade after their discovery. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved. Source

Al-Saleh M.H.,Jordan University of Science and Technology | Sundararaj U.,University of Calgary
Journal of Polymer Science, Part B: Polymer Physics | Year: 2012

Processing, electrical, and electromagnetic interference (EMI) shielding behaviors of carbon nanotube (CNT)/acrylonitrile-butadiene-styrene (ABS) nanocomposites were studied as function of CNT concentration. The nanocomposites were prepared by melt mixing followed by compression molding. The selective and good level of dispersion of CNT in the styrene-acrylonitrile section of the ABS polymer was found to create conductive networks in the ABS matrix at a nanofiller loading of 0.75 wt %. At this nanofiller loading, the nanocomposite electrical conductivity was 10 -5 S/m. This conductivity makes the nanocomposite suitable for electrostatic discharge protection applications. The EMI shielding effectiveness of the nanocomposites increased with the increase in nanofiller concentration. In the 100-1500 MHz frequency range, 1.1 mm thick plates made of ABS nanocomposite filled with 5 wt % CNT exhibit an EMI shielding effectiveness of 24 dB. At this shielding level, the nanocomposite is suitable for a broad range of applications. © 2012 Wiley Periodicals, Inc. Source

Naugler C.,University of Calgary
Clinica Chimica Acta | Year: 2014

Utilization, particularly in chemistry and molecular testing, is growing rapidly in Canada at a time when laboratory budgets are shrinking. Canadian laboratories face particular challenges as the prevailing funding model limits the scope for new revenue generation. Aggressive and coordinated interventions to reduce over-utilization will be necessary to ensure the long-term viability of the current system. © 2013 Elsevier B.V. Source

To determine the effect of tree canopy composition on understory species abundance, three-hundred 2 m × 2-m quadrats from 30 high-latitude boreal forest stands were sampled. In addition, all trees within a 3mradius of each quadrat center and ≥1 m tall were also measured for height, basal diameter, and canopy width (n = 3130). Stands were 33-178 years old, with canopies of Populus tremuloides (trembling aspen) and Picea spp. (spruce) in varying proportions. Arctostaphylos uva-ursi, Calamagrostis purpurascens, Chamerion angustifolium, Shepherdia canadensis, and Hylocomium splendens were the most frequent understory species among quadrats. Scatterplots of P. tremuloides and individual vascular understory species cover values lacked bivariate trends, but the understory species had distinct maxima that ranged from 20 to 90%. A moderately strong correlation (r = 0.52, P <0.001) occurred between P. tremuloides canopy and total vascular understory plant covers, but weak individual species correlations (r = 0.22-0.35, P <0.001), suggested understory species variation was primarily determined by factors other than the amount of immediately overhead canopy cover. Canonical correlation analysis (R = 0.82, P <0.001) indicated that greater vascular understory plant cover occurred when forest stands consisted of P. tremuloides with large canopies and large basal diameters, and lacked Picea. Maximum cover for vascular understory species declined when Picea cover exceeded 7-10%. In combination, P. tremuloides stem densities or a metric based on summed canopy areas converted to a diameter value (canopy-area diameter), and the vertical silhouette area of Picea canopies (canopy profile area), as independent linear regression variables, explained ∼79% of the variance in total vascular understory plant cover. Several Picea basal areaderived metrics were strongly and positively associated with increasing H. splendens cover, but canopy profile area was more informative. Populus tremuloides canopy area and Picea canopy profile area, as indicators of shading, may be important determinants of vascular understory vegetation abundance in stands where solar radiation enters at angles of up to 52°during the summer. Source

Naugler C.T.,University of Calgary
Theoretical Biology and Medical Modelling | Year: 2010

Background: The population dynamics of the various clones of cancer cells existing within a tumour is complex and still poorly understood. Cancer cell clones can be conceptualized as sympatric asexual species, and as such, the application of theoretical population genetics as it pertains to asexual species may provide additional insights. Results. The number of generations of tumour cells within a cancer has been estimated at a minimum of 40, but high cancer cell mortality rates suggest that the number of cell generations may actually be in the hundreds. Such a large number of generations would easily allow natural selection to drive clonal evolution assuming that selective advantages of individual clones are within the range reported for free-living animal species. Tumour cell clonal evolution could also be driven by variation in the intrinsic rates of increase of different clones or by genetic drift. In every scenario examined, the presence of cancer stem cells would require lower selection pressure or less variation in intrinsic rates of increase. Conclusions. The presence of cancer stem cells may result in more rapid clonal evolution. Specific predictions from theoretical population genetics may lead to a greater understanding of this process. © 2010 Naugler ; licensee BioMed Central Ltd. Source

Kalev A.,University of New Mexico | Gour G.,University of Calgary
New Journal of Physics | Year: 2014

We generalize the concept of mutually unbiased bases (MUB) to measurements which are not necessarily described by rank one projectors. As such, these measurements can be a useful tool to study the long-standing problem of the existence of MUB. We derive their general form, and show that in a finite, d-dimensional Hilbert space, one can construct a complete set of mutually unbiased measurements. Besides their intrinsic link to MUB, we show that these measurements' statistics provide complete information about the state of the system. Moreover, they capture the physical essence of unbiasedness, and in particular, they satisfy a non-trivial entropic uncertainty relation similar to MUB. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Source

Fong P.W.L.,University of Calgary
Proceedings - IEEE Symposium on Security and Privacy | Year: 2011

In Facebook-style Social Network Systems (FSNSs), which are a generalization of the access control model of Facebook, an access control policy specifies a graph-theoretic relationship between the resource owner and resource accessor that must hold in the social graph in order for access to be granted. Pseudonymous identities may collude to alter the topology of the social graph and gain access that would otherwise be forbidden. We formalize Denning's Principle of Privilege Attenuation (POPA) as a run-time property, and demonstrate that it is a necessary and sufficient condition for preventing the above form of Sybil attacks. A static policy analysis is then devised for verifying that an FSNS is POPA compliant (and thus Sybil free). The static analysis is proven to be both sound and complete. We also extend our analysis to cover a peculiar feature of FSNS, namely, what Fong et al. dubbed as Stage-I Authorization. We discuss the anomalies resulted from this extension, and point out the need to redesign Stage-I Authorization to support a rational POPA-compliance analysis. © 2011 IEEE. Source

Background: The 2010 International Consensus Algorithm for the Diagnosis, Therapy and Management of Hereditary Angioedema was published earlier this year in this Journal (Bowen et al. Allergy, Asthma & Clinical Immunology 2010, 6:24 - http://www.aacijournal.com/content/6/1/24). Since that publication, there have been multiple phase III clinical trials published on either prophylaxis or therapy of hereditary angioedema and some of these products have changed approval status in various countries. This manuscript was prepared to review and update the management of hereditary angioedema.Objective: To review approaches for the diagnosis and management of hereditary angioedema (HAE) circa December 2010 and present thoughts on moving from HAE management from international evidence-based consensus to facilitate more local health unit considerations balancing costs, efficacies of treatments, and risk benefits. Thoughts will reflect Canadian and international experiences.Methods: PubMed searches including hereditary angioedema and diagnosis, therapy, management and consensus were reviewed as well as press releases from various pharmaceutical companies to early December 2010.Results: The 2010 International Consensus Algorithms for the Diagnosis, Therapy and Management of Hereditary Angioedema is reviewed in light of the newly published phase III Clinical trials for prevention and therapy of HAE. Management approaches and models are discussed.Conclusions: Consensus approach and double-blind placebo controlled trials are only interim guides to a complex disorder such as HAE and should be replaced as soon as possible with large phase IV clinical trials, meta analyses, data base registry validation of approaches including quality of life and cost benefit analyses, safety, and head-to-head clinical trials investigating superiority or non-inferiority comparisons of available approaches. Since not all therapeutic products are available in all jurisdictions and since health care delivery approaches and philosophy vary between countries, each health care delivery sector will likely devise their own algorithms based on local practicalities for implementing evidence-based guidelines and standards for HAE disease management. Quality-of-life and cost affordability benefit conclusions will likely vary between countries and health care units. Data base registries for rare disorders like HAE should be used to detect early adverse events for new therapies and to facilitate phase IV clinical trials and encourage superiority and non-inferiority comparisons of HAE management approaches. © 2011 Bowen; licensee BioMed Central Ltd. Source

Pringsheim T.,University of Calgary | Gorman D.,University of Toronto
Canadian Journal of Psychiatry | Year: 2012

The use of second-generation antipsychotics (SGAs) in youth has increased considerably. Increases are mainly attributable to treatment of disruptive behaviour disorders (DBDs). Our objective was to review the evidence regarding the efficacy of SGAs for DBDs in youth. Method: We performed a systematic review of all randomized controlled trials (RCTs) of SGAs and placebo for the treatment of DBDs in youth, focusing on efficacy data. Results: Eight RCTs in youth with DBDs were included. Five RCTs evaluated the use of risperidone in youth with the combination of subaverage-borderline IQ and disruptive behaviour-aggression. Single RCTs evaluated the use of risperidone for treatment-resistant aggression in attention-deficit hyperactivity disorder and for the treatment of conduct disorder (CD), and a single RCT evaluated the use of quetiapine for adolescent CD. The efficacy results of each of these studies are described. Conclusion: Four placebo-controlled studies support the short-term efficacy of lowdose risperidone in youth with a subaverage IQ. Placebo-controlled evidence is weak or nonexistent for SGAs other than risperidone, and is weak in youth with an average IQ. Multiple factors likely account for the disconnect between this limited evidence base and the frequent use of SGAs for DBDs in clinical practice. These include extrapolation from studies in youth with autism or a subaverage IQ to normally developing youth; ease of SGA titration and the mistaken perception that little monitoring is required; unavailability of psychosocial treatments; limited familiarity with other pharmacological options; clinical and cultural norms; and the influence of the pharmaceutical industry. Source

Genuis S.J.,University of Alberta | Lipp C.T.,University of Calgary
Science of the Total Environment | Year: 2012

As the prevalence of wireless telecommunication escalates throughout the world, health professionals are faced with the challenge of patients who report symptoms they claim are connected with exposure to some frequencies of electromagnetic radiation (EMR). Some scientists and clinicians acknowledge the phenomenon of hypersensitivity to EMR resulting from common exposures such as wireless systems and electrical devices in the home or workplace; others suggest that electromagnetic hypersensitivity (EHS) is psychosomatic or fictitious. Various organizations including the World Health Organization as well as some nation states are carefully exploring this clinical phenomenon in order to better explain the rising prevalence of non-specific, multi-system, often debilitating symptoms associated with non-ionizing EMR exposure. As well as an assortment of physiological complaints, patients diagnosed with EHS also report profound social and personal challenges, impairing their ability to function normally in society. This paper offers a review of the sparse literature on this perplexing condition and a discussion of the controversy surrounding the legitimacy of the EHS diagnosis. Recommendations are provided to assist health professionals in caring for individuals complaining of EHS. © 2011 Elsevier B.V. Source

Mohassel P.,University of Calgary
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

In this work we show a general construction for transforming any chameleon hash function to a strongly unforgeable one-time signature scheme. Combined with the result of [Bellare and Ristov, PKC 2007], this also implies a general construction of strongly unforgeable one-time signatures from ∑-protocols in the standard model. Our results explain and unify several works in the literature which either use chameleon hash functions or one-time signatures, by showing that several of the constructions in the former category can be interpreted as efficient instantiations of those in the latter. They also imply that any "noticeable" improvement to the efficiency of constructions for chameleon hash functions leads to similar improvements for one-time signatures. This makes such improvements challenging since efficiency of one-time signatures has been studied extensively. We further demonstrate the usefulness of our general construction by studying and optimizing specific instantiations based on the hardness of factoring, the discrete-log problem, and the worst-case lattice-based assumptions. Some of these signature schemes match or improve the efficiency of the best previous constructions or relax the underlying hardness assumptions. Two of the schemes have very fast signing (no exponentiations) which makes them attractive in scenarios where the signer has limited computational resources. © 2011 Springer-Verlag Berlin Heidelberg. Source

Sui R.,University of Calgary | Charpentier P.,University of Western Ontario
Chemical Reviews | Year: 2012

A study was conducted to demonstrate synthesis of metal oxide nanostructures by direct sol-gel chemistry in supercritical fluids (SCF). The emphasis of the investigations was on the physics, chemistry, and engineering aspects of the polycondensation of metal oxide precursors in SCFs, while highlighting the mechanisms of the chemical reactions and nanostructure formation. SCF drying circumvented the liquid-gas interface during vaporization due to its single phase nature, preventing collapse of the solid network from capillary forces during the drying process. The latest developments in the sol-gel technology were marked by the use of organic solvents or SCFs for synthesizing a variety of metal oxides. Another major advantage of using SCFs as reaction media for sol-gel reactions relied on the fact that the resulting materials were readily dried after SCF venting. Source

Fogliatto F.S.,Federal University of Rio Grande do Sul | Da Silveira G.J.C.,University of Calgary | Borenstein D.,Federal University of Rio Grande do Sul
International Journal of Production Economics | Year: 2012

The analysis and implementation of mass customization (MC) systems has received growing consideration by researchers and practitioners since the late 1980s. In this paper we update the literature review on MC presented in a previous paper (Da Silveira, G., Borenstein, D., Fogliatto, F.S., 2001. Mass customization: literature review and research directions. International Journal of Production Economics, 72 (1), 1-13), and identify research gaps to be investigated in the future. Major areas of research in MC, and journals in which works have been published are explored through summary statistics. The result is a concise compendium of the relevant literature produced on the topic in the past decade. © 2012 Elsevier B.V. All rights reserved. Source

Burton J.M.,University of Calgary
Cochrane database of systematic reviews (Online) | Year: 2012

This is an updated Cochrane review of the previous version published (Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD006921. DOI: 10.1002/14651858.CD006921.pub2).Multiple sclerosis (MS), a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS), is characterized by recurrent relapses of CNS inflammation ranging from mild to severely disabling.  Relapses have long been treated with steroids to reduce inflammation and hasten recovery.  However, the commonly used intravenous methylprednisolone (IVMP) requires repeated infusions with the added costs of homecare or hospitalization, and may interfere with daily responsibilities. Oral steroids have been used in place of intravenous steroids, with lower direct and indirect costs. The primary objective was to compare efficacy of oral versus intravenous steroids in promoting disability recovery in MS relapses <= six weeks.  Secondary objectives included subsequent relapse rate, disability, ambulation, hospitalization, immunological markers, radiological markers, and quality of life. A literature search was performed using Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Group's Trials Register (January 2012), abstracts from meetings of the American Academy of Neurology (2008-2012), the European Federation of Neurological Sciences (2008-2012), the European Committee for Treatment and Research in Multiple Sclerosis and American Committee for Treatment and Research in Multiple Sclerosis (2008-2012) handsearching. No language restrictions were applied. Randomized or quasi-randomized trials comparing oral versus intravenous steroids for acute relapses (<= six weeks) in patients with clinically definite MSover age 16 were eligible. Three review authors (JB, PO and MH) participated in the independent assessment of all published articles as potentially relevant to the review. Any disagreement was resolved by discussion among review authors.We contacted study authors for additional information.Methodological quality was assessed by the same three review authors. Relevant data were extracted, and effect size was reported as mean difference (MD), mean difference (MD), odds ratio (OR) and absolute risk difference (ARD). With this current update, a total of five eligible studies (215 patients) were identified. Only one outcome, the proportion of patients with Expanded Disability Status Scale (EDSS) improvement at four weeks, was common to three trials, while two trials examined magnetic resonance imaging (MRI) outcomes. The results of this review shows there is no significant difference in relapse recovery at week four (MD -0.22, 95% confidence interval (95% CI), 0.71 to 0.26, P = 0.20) nor differences in magnetic resonance imaging (MRI) gadolinium enhancement activity based on oral versus intravenous steroid treatment. However, only two of the five studies employed more current and rigorous methodological techniques, so these results must be taken with some caution. The Oral Megadose Corticosteroid Therapy of Acute Exacerbations of Multiple Sclerosis (OMEGA) trial and the "Efficacy and Safety of Methylprednisolone Per os Versus IV for the Treatment of Multiple Sclerosis (MS) Relapses" (COPOUSEP) trial, designed to address such limitations, are currently underway. The analysis of the five included trials comparing intravenous versus oral steroid therapy for MS relapses do not demonstrate any significant differences in clinical (benefits and adverse events), radiological or pharmacological outcomes. Based on the evidence, oral steroid therapy may be a practical and effective alternative to intravenous steroid therapy in the treatment of MS relapses. Source

Aghoram R.,University of Calgary
Cochrane database of systematic reviews (Online) | Year: 2012

Chronic hepatitis B virus infection is a risk factor for development of hepatocellular carcinoma. Alpha-foetoprotein and liver ultrasonography are used to screen patients with chronic hepatitis B for hepatocellular carcinoma. It is uncertain whether screening is worthwhile. To determine the beneficial and harmful effects of alpha-foetoprotein or ultrasound, or both, for screening of hepatocellular carcinoma in patients with chronic hepatitis B virus infection. Electronic searches were performed until December 2011 in the Cochrane Hepato-Biliary Group Controlled Trials Register (December 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (2011, Issue 4) in The Cochrane Library, MEDLINE (1948 to 2011), EMBASE (1980 to 2011), Science Citation Index Expanded (1900 to 2011), Chinese Medical Literature Electronic Database (WanFang Data 1998 to 2011), and Chinese Knowledge Resource Integrated Database (1994 to 2011). All published reports of randomised trials on screening for liver cancer were eligible for inclusion, irrespective of language of publication. Studies were excluded when the hepatitis B status was uncertain, the screening tests were not sensitive or widely-used, or when the test was used for diagnosis of hepatocellular carcinoma rather than screening. We independently analysed all the trials considered for inclusion. We wrote to the authors of one of the trials to obtain further information. Three randomised clinical trials were included in this review. All of them had a high risk of bias. One trial was conducted in Shanghai, China. There are several published reports on this trial, in which data were presented differently. According to the 2004 trial report, participants were randomised to screening every six months with alpha-foetoprotein and ultrasonography (n = 9373) versus no screening (n = 9443). We could not draw any definite conclusions from it. A second trial was conducted in Toronto, Canada. In this trial, there were 1069 participants with chronic hepatitis B. The trial compared screening every six months with alpha-foetoprotein alone (n = 532) versus alpha-foetoprotein and ultrasound (n = 538) over a period of five years. This trial was designed as a pilot trial; the small number of participants and the rare events did not allow an effective comparison between the two modes of screening that were studied. The remaining trial, conducted in Taiwan and published as an abstract, was designed as a cluster randomised trial to determine the optimal interval for screening using alpha foetoprotein and ultrasound. Screening intervals of four months and 12 months were compared in the two groups. Further details about the screening strategy were not available. The trial reported on cumulative four-year survival, cumulative three-year incidence of hepatocellular carcinoma, and mean tumour size. The cumulative four-year survival was not significantly different between the two screening intervals. The incidence of hepatocellular cancer was higher in the four-monthly screening group. The included trials did not report on adverse events. It appears that the sensitivity and specificity of the screening modes were poor, accounting for a substantial number of false-positive and false-negative screening results. There is not enough evidence to support or refute the value of alpha-foetoprotein or ultrasound screening, or both, of hepatitis B surface antigen (HBsAg) positive patients for hepatocellular carcinoma. More and better designed randomised trials are required to compare screening against no screening. Source

Raju T.N.K.,U.S. National Institutes of Health | Singhal N.,University of Calgary
Clinics in Perinatology | Year: 2012

This article provides a brief overview of pros and cons of clamping the cord too early (within seconds) after birth. It also highlights evolving data that suggest that delaying cord clamping for 30 to 60 seconds after birth is beneficial to the baby, with no measurable negative effects either the baby or the mother. © 2012. Source

Cox R.G.,University of Calgary
Canadian Journal of Anesthesia | Year: 2014

Summary: Author: Francis G. Ruston MD Citation: Ruston FG. Epidural anaesthesia in infants and children. Can Anaesth Soc J 1954: 1: 37-44. Purpose: The author describes the use of single-shot epidural anesthesia in a series of 44 infants and children. The patients were anesthetized in hospitals in Hamilton, Ontario from 1949 until the time of publication in 1954. The study aimed to describe the indications and efficacy of this technique as well as any apparent complications. A detailed description of the management of these patients was given, including many tips and suggestions that are still applicable in 2013. Principal findings: Seventy-seven infants and children received epidural anesthesia for a variety of procedures, particularly for pyloric stenosis. Forty-four of the procedures were carried out by the author. All patients survived, apart from one child who died of recurrent intestinal obstruction unrelated to the anesthetic. It was found, after some experience, that the sitting position was preferable for epidural needle insertion. Use of the hanging drop technique for identification of the epidural space proved to be simple and reliable. Surgical conditions were found to be excellent and relaxation was profound; however, some sedation was often required to obtain optimal conditions for surgery. The surgeons became sold on the technique and began to request an epidural on a regular basis. Conclusions: Epidural anesthesia in infants and young children is effective for a variety of procedures below the diaphragm, even in moribund patients. © 2013 Canadian Anesthesiologists' Society. Source

The crystal structures of the isostructural orthorhombic sulfates celestite (SrSO 4), anglesite (PbSO 4), and barite (BaSO 4) were refined by Rietveld methods using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Their structural model was refined in space group Pbnm. The unit-cell parameters are a = 6.87032(3), b = 8.36030(5), c = 5.34732(1) Å, and V = 307.139(3) Å3 for SrSO 4; a = 6.95802(1), b = 8.48024(3), c = 5.39754(1) Å, and V = 318.486(1) Å3 for PbSO 4; and a = 7.15505(1), b = 8.88101(3), c = 5.45447(1) Å, and V = 346.599(1) Å3 for BaSO 4. The average [12] distances are 2.827(1), 2.865(1), and 2.953(1) Å for SrSO 4, PbSO 4, and BaSO 4, respectively, and their corresponding average [4] distances are 1.480(1), 1.477(3), and 1.471(1) Å. The geometrical features of the SO 4 and MO12 polyhedra become more symmetrical from SrSO 4 to BaSO 4. Across the series, the a, b, and c parameters vary non-linearly with increasing V. The radii of the M 2+ cations, rM, [12], and [4] distances vary linearly with V. These structural trends arise from the effective size of the M 2+ cation (rM: Sr < Pb < Ba) that is coordinated to 12 O atoms. Copyright © 1997-2012 Mineralogical Society of America. Source

Friedrich M.G.,University of Calgary
Nature Reviews Cardiology | Year: 2010

Edema is a generic component of the tissue response to acute injury and, therefore, an important diagnostic target for assessing the acuity of tissue damage in vivo. In the past, edema could not be used as a diagnostic target, because even histological techniques failed to provide reliable qualitative or even quantitative data on its presence, extent, and regional distribution. Cardiac MRI is about to change that. Using water-sensitive MRI, visualization of myocardial edema in vivo is possible within a few breath holds, without using radiation or contrast agents. Edema imaging provides useful incremental diagnostic and prognostic information in a variety of clinical settings associated with suspected acute myocardial injury. In combination with scar imaging, MRI differentiates reversible from irreversible injury and can quantify myocardial salvage after coronary revascularization. With this unique contribution, MRI of edema should be considered an essential diagnostic tool and, as part of a multitarget MRI scan, illustrates the exceptional role of comprehensive cardiac MRI in diagnosing and staging myocardial diseases safely and efficiently. © 2010 Macmillan Publishers Limited. All rights reserved. Source

Paradigm families and paradigm practice moments have shown me that therapeutic conversations between nurses and families can profoundly and positively change illness beliefs in family members and nurses and contribute to healing from serious illness. The integration of brain science into nursing practice offers further understanding of the importance of illness beliefs and the role they may play in helping individual and family healing. Brain science offers explanations that connect how certain family nursing interventions that soften suffering and challenge constraining illness beliefs may result in changes in brain structure and functioning. New illness beliefs may result in new neural pathways in the brain, and therefore, possibilities for a new way of being in relationship with illness and in relationship with others can also develop. Newly acquired practice skills and interventions that have emerged from an understanding of brain science plus the reemphasis of other interventions utilized in the Illness Beliefs Model are offered to enhance our care of families suffering with illness. © The Author(s) 2015. Source

Wallace J.L.,University of Calgary | Wallace J.L.,University of Toronto | Wang R.,Lakehead University
Nature Reviews Drug Discovery | Year: 2015

Hydrogen sulfide (H 2 S) has become recognized as an important signalling molecule throughout the body, contributing to many physiological and pathological processes. In recent years, improved methods for measuring H 2 S levels and the availability of a wider range of H 2 S donors and more selective inhibitors of H 2 S synthesis have helped to more accurately identify the many biological effects of this highly reactive gaseous mediator. Animal studies of several H 2 S-releasing drugs have demonstrated considerable promise for the safe treatment of a wide range of disorders. Several such drugs are now in clinical trials. © 2015 Macmillan Publishers Limited. Source

Beauchamp B.,University of Calgary | Grasby S.E.,Geological Survey of Canada
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012

The Upper Carboniferous to Upper Permian deposits of the Sverdrup Basin (Arctic Canada) record a transition from carbonate to silica dominated shallow shelf ecosystems. Chert expansion started during the latest Carboniferous in distal deep-water slope environments when prolific warm-water, photozoan carbonate factories developed on the adjacent shallow shelves. A shift to heterozoan factories during the Sakmarian-Artinskian was caused by the introduction of cooler water in response to paleoceanographic changes along NW Pangea. By Kungurian time, heterozoan carbonate factories narrowed substantially while hyalosponge factories had expanded well into the mid shelves. A brief return to widespread heterozoan carbonate sedimentation occurred during the Wordian, followed by further encroachment of shallow shelves by biosiliceous factories during the Capitanian and Wuchiapingian. A major drop in relative rates of carbonate sediment accumulation with time suggests both carbonate and biosiliceous factories were under considerable stress prior to the Late Permian Extinction event. It is proposed that Sverdrup Basin waters became progressively more acidic in response to build up of atmospheric CO 2 throughout the Permian which led to a gradual shoaling of the lysocline and the calcite compensation depth, which was amplified by upwelling along the northwestern margin of Pangea. Ocean acidification initiated in response to amalgamation of the Pangea supercontinent. This inhibited the silicate weathering-response through development of thick protective soil blankets. A temperature shock associated with the extinction event led to a major fall of the lysocline allowing carbonates to resume accumulation in spite of low pH conditions. The subsequent die off of terrestrial vegetation, stripping of soil cover, widespread continental erosion and repeated exposures of fresh rock surfaces associated with a major base level shift allowed silicate weathering to restart and drive oceans back to carbonate saturation. © 2012. Source

Howlett J.G.,University of Calgary
Canadian Journal of Cardiology | Year: 2014

The widespread acceptance of heart-failure (HF) clinics is based on studies with poor and poorly-described care. This led to HF-clinic proliferation, often with access for a small percentage of younger, healthier and generally affluent patients. This system fails to provide the essential timely access to specialist-team consultation following hospital-discharge. Recent well-conducted randomized trials of HF-clinic care found no benefit over usual care. To provide optimal value, HF-clinics must evolve to devote resources to timely assessment/reassessment and close follow-up of selected high-risk/advanced HF patients, along with timely support of the primary-care team that will assure the bulk of routine HF care. © 2014 Canadian Cardiovascular Society. Source

Harkness K.L.,Queens University | Stewart J.G.,Queens University | Wynne-Edwards K.E.,University of Calgary
Psychoneuroendocrinology | Year: 2011

This study examined the hypothesis that depressed adolescents with a history of childhood maltreatment will show greater cortisol reactivity to psychological stress challenge than those without, and this relation will be moderated by level of depression severity. Seventy-one adolescents were exposed to the Trier Social Stress Test. Salivary cortisol was assessed at baseline, immediately before the challenge, after the challenge, and during an extended recovery period. Childhood maltreatment was assessed with a rigorous contextual interview and rating system. Adolescents with a history of maltreatment produced higher and more prolonged levels of cortisol in response to the challenge than did adolescents with no maltreatment, but only among those with a mild/moderate level of depression severity. Those with moderate/severe depression exhibited a blunted cortisol response regardless of child maltreatment history. These findings indicate that depression is a heterogeneous syndrome, and that both depression severity and child maltreatment history should be considered in studies examining biological stress reactivity. © 2010 Elsevier Ltd. Source

Wallace J.L.,University of Calgary | Ianaro A.,University of Naples | Flannigan K.L.,Georgia State University | Cirino G.,University of Naples
Seminars in Immunology | Year: 2015

There are numerous gaseous substances that can act as signaling molecules, but the best characterized of these are nitric oxide, hydrogen sulfide and carbon monoxide. Each has been shown to play important roles in many physiological and pathophysiological processes. This article is focused on the effects of these gasotransmitters in the context of inflammation. There is considerable overlap in the actions of nitric oxide, hydrogen sulfide and carbon monoxide with respect to inflammation, and these mediators appear to act primarily as anti-inflammatory substances, promoting resolution of inflammatory processes. They also have protective and pro-healing effects in some tissues, such as the gastrointestinal tract and lung. Over the past two decades, significant progress has been made in the development of novel anti-inflammatory and cytoprotective drugs that release of one or more of these gaseous mediators. © 2015 Elsevier Ltd. Source

Cai C.,Central South University | Gao Y.,LIAONING Technical University | Gao Y.,University of Calgary
GPS Solutions | Year: 2013

A combination of GPS and GLONASS observations can offer improved reliability, availability and accuracy for precise point positioning (PPP). We present and analyze a combined GPS/GLONASS PPP model, including both functional and stochastic components. Numerical comparison and analysis are conducted with respect to PPP based on only GPS or GLONASS observations to demonstrate the benefits of the combined GPS/GLONASS PPP. The observation residuals are analyzed for more appropriate stochastic modeling for observations from different navigation systems. An analysis is also made using different precise orbit and clock products. The performance of the combined GPS/GLONASS PPP is assessed using both static and kinematic data. The results indicate that the convergence time can be significantly reduced with the addition of GLONASS data. The positioning accuracy, however, is not significantly improved by adding GLONASS data if there is a sufficient number of GPS satellites with good geometry. © 2012 Springer-Verlag. Source

The human ether-a-go-go related gene 1 (hERG1), which codes for a potassium ion channel, is a key element in the cardiac delayed rectified potassium current, IKr, and plays an important role in the normal repolarization of the heart's action potential. Many approved drugs have been withdrawn from the market due to their prolongation of the QT interval. Most of these drugs have high potencies for their principal targets and are often irreplaceable, thus "rehabilitation" studies for decreasing their high hERG1 blocking affinities, while keeping them active at the binding sites of their targets, have been proposed to enable these drugs to re-enter the market. In this proof-of-principle study, we focus on cisapride, a gastroprokinetic agent withdrawn from the market due to its high hERG1 blocking affinity. Here we tested an a priori strategy to predict a compound's cardiotoxicity using de novo drug design with molecular docking and Molecular Dynamics (MD) simulations to generate a strategy for the rehabilitation of cisapride. We focused on two key receptors, a target interaction with the (adenosine) receptor and an off-target interaction with hERG1 channels. An analysis of the fragment interactions of cisapride at human A2A adenosine receptors and hERG1 central cavities helped us to identify the key chemical groups responsible for the drug activity and hERG1 blockade. A set of cisapride derivatives with reduced cardiotoxicity was then proposed using an in-silico two-tier approach. This set was compared against a large dataset of commercially available cisapride analogs and derivatives. An interaction decomposition of cisapride and cisapride derivatives allowed for the identification of key active scaffolds and functional groups that may be responsible for the unwanted blockade of hERG1. Source

Alladin A.,University of Calgary
American Journal of Clinical Hypnosis | Year: 2014

This article synthesizes the concept of "wounded self" in the understanding and psychological treatment of anxiety disorders. The focal point of this concept is the notion of self-wounds or early unresolved emotional injuries. According to this conceptualization, anxiety represents an unconscious fear of unbearable insult to the wounded self, which is protected by maladaptive conscious strategies such as avoidance, cognitive distortions, or emotional constriction. This perspective provides a theoretical basis for blending elements of psychodynamic, behavioral, cognitive, and experiential therapies in the psychological management of anxiety disorders. As cognitive hypnotherapy embodies all of these therapeutic elements, its application to anxiety disorders is described in this article. Various hypnotherapeutic techniques for symptomatic relief and for eliciting and healing the wounded self are discussed and exemplified by a case. This case illustrates that symptom-focused treatment is necessary, but not sufficient. A more durable treatment requires resolution of underlying conflicts that drive the anxiety. © American Society of Clinical Hypnosis. Source

Gailer J.,University of Calgary
Journal of Inorganic Biochemistry | Year: 2012

The etiology of numerous grievous human diseases, including Alzheimer's and Parkinson's Disease is not well understood. Conversely, the concentration toxic metals and metalloids, such as As, Cd, Hg and Pb in human blood of the average population is well established, yet we know strikingly little about the role that they might play in the etiology of disease processes. Establishing functional connections between the chronic exposure of humans to these and other inorganic pollutants and the etiology of certain human diseases is therefore viewed by many as one of the greatest challenges in the post-genomic era. Conceptually, this task requires us to uncover hitherto unknown biomolecular mechanisms which must explain how small doses of a toxic metal/metalloid compound (low μg per day) - or mixtures thereof - may eventually result in a particular human disease. The biological complexity that is inherently associated with mammals, however, makes the discovery of these mechanisms a truly monumental task. Recent findings suggest that a better understanding of the bioinorganic chemistry of inorganic pollutants in the mammalian bloodstream represents a fruitful strategy to unravel relevant biomolecular mechanisms. The adverse effect(s) that toxic metals/metalloid compounds exert on the transport of essential ultratrace elements to internal organs appear particularly pertinent. A brief overview of the effect that arsenite and Hg 2+ exert on the mammalian metabolism of selenium is presented. © 2011 Elsevier Inc. All rights reserved. Source

Cross J.C.,University of Calgary
Current Biology | Year: 2016

Evolutionary gene duplication, developmental endoreduplication and selective gene amplification are alternative strategies for increasing gene copy number. When these processes occur together, things get really interesting, and new work shows that is the lifestyle of cells in the placenta. © 2016 Elsevier Ltd. Source

Cheng Z.,Hong Kong Polytechnic University | Nault B.R.,University of Calgary
Information Systems Research | Year: 2012

We examine how one industry's productivity is affected by the IT capital of its customers and how this effect depends on industries' relative concentration. These customer-driven IT spillovers result from customers' IT investments in various information systems that reduce transaction costs through information sharing and coordination and lead to more efficient production and logistics upstream. The magnitude of IT spillovers depends on relative industry concentration because customers in more concentrated industries relative to those of their suppliers are better able to retain the benefits from their IT investments. We model customer-driven effects based on production theory and empirically test the model using two industry-level data sets covering different and overlapping time periods (1987-1999 and 1998-2005), different scopes of the economy (manufacturing only versus all industries), and different levels of industry aggregation. We find that, given an increase in a downstream industry's IT capital, there is a significant increase in downstream industry output as well as significant increases in upstream industry output. Moreover, the magnitude of IT spillovers is related to relative industry concentration: A 1% decrease in a customer's relative industry concentration increases spillovers by roughly 1%. Thus, further increases in IT capital can be justified along the supply chain, and an industry's relative concentration-which can reflect market power-in part determines the distribution of productivity benefits. © 2012 INFORMS. Source

Nguyen T.,Cardiac Prevention and Rehabilitation | Lau D.C.W.,University of Calgary
Canadian Journal of Cardiology | Year: 2012

Global obesity rates have increased steadily in both developed and emerging countries over the past several decades with little signs of slowing down. Over 1.5 billion people worldwide are overweight or obese and over 40 million children under the age of 5 are overweight. Obesity is associated with increased morbidity, disability, and premature mortality from cardiovascular disease, diabetes, cancers, and musculoskeletal disorders. The personal and societal health and economic burden of this preventable disease pose a serious threat to our societies. Obesity is a major risk factor for hypertension and cardiovascular disease. Weight loss, through health behaviour modification and dietary sodium restriction, is the cornerstone in the treatment of obesity-related hypertension. Pharmacotherapy and bariatric surgery for obesity are adjunctive measures when health behaviour interventions fail to achieve the body weight and health targets. Successful management of overweight and obese persons requires a comprehensive, multifaceted framework that integrates population health, public health, and medical health models to dismantle the proximal and distal drivers of the obesogenic environment in which we live. Prevention of obesity is no longer a lofty but rather necessary goal that urgently calls for action from governments at all levels, in conjunction with all public and private sector stakeholders, in order to combat a serious and growing public health concern. © 2012 Canadian Cardiovascular Society. Source

Cognitive impairment is common in psychosis and has recently been observed in individuals at clinical high risk (CHR) of developing psychosis. The purpose of this study was to characterize longitudinal change in cognition among CHR individuals, and compare cognition of CHR individuals who later convert to psychosis to that of CHR who do not convert. Participants were tested at baseline and followed-up after six months using a comprehensive cognitive test battery. Individuals who did not convert to psychosis either remained stable or significantly improved in their cognitive performance. At baseline participants who converted to psychosis compared to non-converters exhibited poorer performance in several cognitive tests, suggesting that some cognitive impairment is already present before conversion. Future longitudinal research should address if further decline takes place during the prodrome or after conversion to psychosis. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved. Source

Allen D.L.,University of Colorado at Boulder | Hittel D.S.,University of Calgary | McPherron A.C.,U.S. National Institutes of Health
Medicine and Science in Sports and Exercise | Year: 2011

Myostatin is a member of the transforming growth factor-β/bone morphogenetic protein (TGF-β/BMP) superfamily of secreted factors that functions as a potent inhibitor of skeletal muscle growth. Moreover, considerable evidence has accumulated that myostatin also regulates metabolism and that its inhibition can significantly attenuate the progression of obesity and diabetes. Although at least part of these effects on metabolism can be attributable to myostatin's influence over skeletal muscle growth and therefore on the total volume of metabolically active lean body mass, there is mounting evidence that myostatin affects the growth and metabolic state of other tissues, including the adipose and the liver. In addition, recent work has explored the role of myostatin in substrate mobilization, uptake, and/or utilization of muscle independent of its effects on body composition. Finally, the effects of both endurance and resistance exercise on myostatin expression, as well as the potential role of myostatin in the beneficial metabolic adaptations occurring in response to exercise, have also begun to be delineated in greater detail. The purpose of this review was to summarize the work to date on the expression and function of myostatin in obesity, diabetes, and exercise adaptation. © 2011 by the American College of Sports Medicine. Source

Coburn J.,Medical College of Wisconsin | Leong J.,Tufts University | Chaconas G.,University of Calgary
Trends in Microbiology | Year: 2013

The Lyme disease spirochetes, Borrelia burgdorferi (sensu lato), must cause persistent, disseminated infection to be maintained in the natural enzootic cycle. In human Lyme disease, spirochetes spread from the site of a tick bite to colonize multiple tissue sites, causing multisystem clinical manifestations. The Lyme spirochetes produce many adhesive surface proteins that collectively recognize diverse host substrates and cell types and are likely to promote dissemination and chronic infection in a variety of tissues. Recent application of state-of-the-art in vivo imaging technologies is illuminating mechanisms of interaction of B. burgdorferi with the host and the importance of multiple adhesins during mammalian infection. © 2013 Elsevier Ltd. Source

Howlett J.G.,University of Calgary
Canadian Journal of Cardiology | Year: 2011

Acute heart failure (AHF) affects nearly every Canadian with heart failure (HF) at least once. Despite several attempts, no medical therapies have been shown to improve the natural history of AHF. In addition, the place of diagnosis of AHF is increasingly made in the outpatient setting. In this view, AHF is a moving target, and from recent registry data and from clinical trials, 5 critical lessons regarding the syndrome of AHF emerge: (1) The period of clinical instability preceding AHF may be much longer than previously thought. (2) Refinement of tools used to aid the early and accurate diagnosis of AHF will impact patient outcomes. (3) Standard supportive care of patients with AHF includes early use of diuretics with frequent reassessment in nearly all patients and supplemental vasodilators and oxygen therapy in selected cases. (4) Patients who survive presentation of AHF continue to suffer high rates of re-presentation, death, and rehospitalization following discharge from either hospital or emergency department. (5) Interventions shown to improve patient outcomes for AHF to date are related to process of care rather than new medications or devices. This report reviews the recent literature regarding the presentation, diagnosis, management, and prognosis of AHF. Areas of future research priority are indicated and guidelines for improving treatment are provided. AHF is an important clinical area that has not been as intensively studied as chronic HF; it presents both important needs and exciting opportunities for research and innovation. © 2011 Canadian Cardiovascular Society. Source

Lai D.W.L.,University of Calgary
Journal of Elder Abuse and Neglect | Year: 2011

The traditional values of Chinese culture promote care and respect toward older adults. While it appears to be ironic to discuss issues of abuse and neglect in the Chinese culture, research findings in Chinese societies do indicate the occurrences of such problems. However, little research on the abuse and neglect of older Chinese in Western societies has been available. This study aims to examine the incidence of abuse and neglect and the associated correlates based on data collected from a random sample of 2,272 aging Chinese 55 years and older in seven Canadian cities. The findings show that 4.5% of the participants reported experiencing at least one incident of maltreatment or neglect within the past year. The most common forms of neglect and abuse experienced by the aging Chinese include being scolded, yelled at, treated impolitely all the time, and ridiculed. Close family members such as spouses and sons are those that most commonly maltreat older Chinese. Those who were more likely to report at least one incident of maltreatment or neglect were older adults living with others; they tended to have no education, more access barriers, more chronic illnesses, less favorable mental health, and a higher level of identification with Chinese cultural values. The findings implied that the face value of respect and care received by older people in Chinese culture should not be taken for granted. Culturally appropriate. © Taylor & Francis Group, LLC. Source

Mukhopadhyay S.,University of Calgary | Banerjee S.,Polytechnic University of Turin
Expert Systems with Applications | Year: 2012

The control and estimation of unknown parameters of chaotic systems are a daunting task till date from the perspective of nonlinear science. Inspired from ecological co-habitation, we propose a variant of Particle Swarm Optimization (PSO), known as Chaotic Multi Swarm Particle Swarm Optimization (CMS-PSO), by modifying the generic PSO with the help of the chaotic sequence for multi-dimension unknown parameter estimation and optimization by forming multiple cooperating swarms. This achieves load balancing by delegating the global optimizing task to concurrently operating swarms. We apply it successfully in estimating the unknown parameters of an autonomous chaotic laser system derived from Maxwell-Bloch equations. Numerical results and comparison demonstrate that for the given system parameters, CMS-PSO can identify the optimized parameters effectively evolving at each iteration to attain the pareto optimal solution with small population size and enhanced convergence speedup. © 2011 Elsevier Ltd. All rights reserved. Source

There is a long history in ecology of studying the mechanisms that may promote the long-term co-occurrence of phytoplankton, and zooplankton to a lesser degree, in aquatic systems. The recent emergence of using phylogenetic information to understand community assembly may represent a new tool for tackling old questions about competition in plankton, although studies using such methods in this way are rare to date. Here, I provide an overview of the general methods developed in related studies, briefly review existing works, and discuss various conceptual and methodological challenges that researchers should be aware of before applying these methods to plankton communities. Source

Mee J.A.,University of Calgary | Moore J.-S.,Laval University
Journal of Biogeography | Year: 2014

Pleistocene microrefugia (or cryptic refugia) may be distinguished from macrorefugia (or conventional refugia) on the basis of two characteristics. First, microrefugia were smaller than macrorefugia and consequently supported smaller refugial populations. Second, microrefugia harboured less diverse biotic communities than macrorefugia. We propose that these characteristics have important implications for the ecology and evolution of species and populations that have a history of isolation in microrefugia. We propose four hypotheses regarding the evolution of microrefugial populations: (1) small effective population sizes associated with survival in microrefugia lead to reduced genetic diversity and influence the evolution of mating systems; (2) differences in environmental conditions between macro- and microrefugia lead to local adaptation; (3) reduced diversity increases ecological opportunity and promotes ecological divergence in microrefugia; and (4) reduced species diversity in microrefugia allows more specific species interactions and promotes coevolution among species. We urge biogeographers to study the evolutionary implications of isolation in microrefugia. © 2013 John Wiley & Sons Ltd. Source

Santamaria P.,University of Calgary
Immunity | Year: 2010

Autoimmune diseases with high population prevalence such as type 1 diabetes (T1D) develop as a result of ill-defined interactions between putative environmental triggers and a constellation of genetic elements scattered throughout the genome. In T1D, these interactions somehow trigger a loss of tolerance to pancreatic β cells, manifested in the form of a chronic autoimmune response that mobilizes virtually every cell type of the immune system and progressively erodes the host's β cell mass. The five accompanying review articles focus on key areas of T1D research, ranging from genetics and pathogenesis to prediction and therapy. Here, I attempt to integrate and bring into focus the most salient points of these reviews in the context of other findings, with an emphasis on identifying knowledge gaps and research opportunities. © 2010 Elsevier Inc. Source

Liao W.,University of Calgary
Inverse Problems in Science and Engineering | Year: 2011

The objective of this article is to develop a computational method, which combines an efficient high-order finite difference method for solving wave equation, auto differentiation tools and globally convergent optimization algorithms to estimate the unknown coefficient in a 1-D wave equation. The forward problem is solved by efficient and higher order finite difference methods while the gradient of the cost functional with respect to the coefficient is calculated by an adjoint code which is generated by an auto differentiation tool, such as Tangent linear and Adjoint Model Compiler. Three numerical examples are conducted to demonstrate the effectiveness, robustness and accuracy of the proposed computational method. © 2011 Taylor & Francis. Source

Since 2000, Escherichia coli producing CTX-M enzymes (especially CTX-M-15) have emerged worldwide as important causes of community-onset urinary tract infections (UTIs) and bloodstream infections due to extended-spectrum β-lactamase (ESBL)-producing bacteria. Molecular epidemiology studies suggested that the sudden worldwide increase of CTX-M-15-producing E. coli is mostly due to a single clone named ST131 and that foreign travel to high-risk areas such as the Indian subcontinent might in part play a role in the spread of this clone across different continents. Empirical antibacterial coverage for these resistant organisms should be considered in community patients presenting with sepsis involving the urinary tract especially if a patient recently travelled to a high-risk area. Infections due to ESBL-producing Enterobacteriaceae are associated with a delay in initiation of appropriate antibacterial therapy, which consequently prolongs hospital stays and increases hospital costs. Failure to initiate appropriate antibacterial therapy from the start appears to be responsible for higher patient mortality. The carbapenems are widely regarded as the drugs of choice for the treatment of severe infections due to ESBL-producing Enterobacteriaceae, although comparative clinical trials are lacking. Agents that may be useful for the treatment of ESBL-associated UTIs include fosfomycin, nitrofurantoin and temocillin. If this emerging public health threat is ignored, it is possible that clinicians may be forced in the near future to use the carbapenems as the first choice for empirical treatment of serious infections associated with UTIs originating from the community.© 2010 Adis Data Information BV. All rights reserved. Source