Natural Sciences And Engineering Research Council Of Canada Research Articles

Evaluating Three‐dimensional (3D) Digital Models of Anatomical Variations as Assessment Tools for Undergraduate and Graduate Anatomy Education

IntroductionFor medical and allied health students, knowledge of anatomical variation is important as it may influence physical examination, diagnosis and treatment of patients. Recent studies indicate anatomical variation should be conceptually integrated early into the anatomy curriculum prior to the discipline specific variations taught in surgical and radiological postgraduate training programs. For academic institutions with limited access to cadaveric dissection and anatomy museums, the opportunity for students to appreciate the range of normality in anatomical structures is diminished. Thus, the purpose of this study was to demonstrate how 3D models of anatomical variations may be used to assess structure, function and spatial relationships by incorporating the concept of anatomical variations into assessment paradigms.MethodsTwo 3D digital models depicting upper limb muscular variations, and a 3D teratological model were evaluated by undergraduate kinesiology (KIN) (n = 30), and graduate clinical anatomy (CA) (n = 10) students. The study protocol consisted of the following instruments introduced in sequence: (1) 30‐question Spatial Ability Test (SAT), (2) 16‐question baseline upper limb anatomy test, (3) 13‐question multiple choice quiz based on the displayed 3D models, and (4) Student perception survey (5‐point Likert scale). Based on SAT scores, a median split was used stratify the students into high (KIN: 15, CA: 5) and low spatial ability (KIN: 15, CA: 5). All data are presented as Mean ± SD.ResultsBoth student groups scored similarly on the baseline anatomy knowledge test (KIN: 71 ± 17 %, CA: 71 ± 12%). The mean 3D model quiz scores for KIN students of high spatial ability were 72 ± 16% compared to those of lower spatial ability, 68 ± 14%. The 3D model quiz scores for CA students of high spatial ability were 88 ± 12% compared to CA students of lower spatial ability, 77 ± 15%. The models were perceived as useful in assessing spatial relationships (KIN: 4.4 ± 0.8, CA: 4.9 ± 0.3) and clinical concepts (KIN: 4.0 ± 0.9 CA: 3.9 ± 0.3). Student perceptions were positive for integrating the 3D models into lecture, or laboratory discussions, but KIN students were relatively neutral (3.2 ± 1.2) compared to CA students (3.9 ± 0.3) in their integrated use in bell‐ringer style laboratory assessments. The students expressed interest for a database of explorable 3D models of anatomical variations.ConclusionIntegration of the 3D variant models into anatomy curricula could be a useful means in assessing fundamental anatomical concepts, while demonstrating how deviations in structure can affect normal function. For institutions with computer access but limited cadaveric resources, the 3D models could be powerful supplementary teaching and assessment tools for anatomy students of all education levels and spatial abilities. Furthermore, development of a database of explorable anatomical variations for teaching and learning purposes would be valuable for allied health and medical programs in search of integrating variant anatomy into their anatomy curricula.Support or Funding InformationSupported by: American Association of Anatomists (AAA) Education Research Scholarship; Natural Sciences and Engineering Research Council of Canada (NSERC)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cerebral Aneurysmal Coiling in Virtual Reality ‐ An Overview of Novice Skill Development

Introduction and AimsCerebral endovascular aneurysm coiling is an interventional angiography technique which requires the use of fine motor and visuo‐spatial skills in order to guide tools throughout relevant vascular anatomy and deposit coils within the aneurysm. With the help of quantitatively limited fluoroscopy, coils are established through microcatheter placement in the aneurysm neck and electrolytically detached after their appropriate rotation and positioning. This procedure requires, and is currently limited to, extensive clinical training in the AngioSuite, where trainees are closely supervised by a consultant. This approach, although providing the current gold standard in training, limits the pace of skill development, exposes patients to unnecessary risk and wastes valuable monetary and personnel resources. The development of the skills needed for these procedures can be facilitated by 3D simulator‐based training. Simulation‐based medical education has recently started focusing on personalized training in reducing errors and development of specific skills.The ANGIO Mentor visual‐haptic simulator has been regarded as an effective training tool, increasing performance in diagnostic cerebral angiography, however, this simulator has not been tested thoroughly in its ability to train interventional skills. In particular, the details of the aneurysm coiling process during simulation‐based training have not been assessed.MethodsIn this study, 12 novice medical students were given simulation‐based diagnostic cerebral angiography training until a procedural plateau in performance, established in our previous work (Zaika et al., 2016). Subsequently, they were trained using video tutorials and written instructions to identify, measure and intervene with cerebral aneurysms using endovascular coils. Over the span of 6 sessions, participants were assessed on their procedural pace, coiling quantity and quality, and perforation rates. Concurrently, their spatial ability was assessed using a mental rotations test (MRT) and used in the performance analysis.Results and DiscussionWe found that all individuals were able to perform the procedure faster after 6 sessions, reducing their average time from 42 to 24 minutes. Coil success rate improved over from 82% to 88% and coil packing rate remained consistent at 30% throughout testing. High perforation rate seen at the start of the study showed a trend of decreasing over the latter sessions, however, over half of aneurysms were still being perforated by the novice participants. No change in aneurysm coiling quality was found, with a slight decrease in number of parent artery coil protrusions. High MRT individuals were also better able to establish guider catheter and associate tools prior to coiling. This work identifies the utility of simulation‐based cerebral angiography training in identifying the particular difficulties trainees experience in learning procedural skills, including prevention of perforations, proper positioning and success of coils within the aneurysm.Support or Funding InformationThis research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canadian Institutes of Health Research (CIHR).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Autophagy and mitophagy flux in skeletal muscle during chronic‐contractile activity

Autophagy and mitophagy are important cellular recycling mechanisms, however the regulation of autophagy and mitophagy flux in training‐induced muscle adaptations remains to be elucidated. Using the microtubule destabilizer colchicine (0.04 mg/kg), this study assessed LC3II and p62 flux in skeletal muscles of Sprague‐Dawley rats (501 ± 9 g) subjected to chronic contractile activity (CCA; 3 hours/day, 9V, 10 Hz continuous, 0.1 ms pulse duration) for 1, 2, 3, 5, and 7 days (N=6–8/group). Colchicine was given via an intraperitoneal injection 48 hours prior to tissue collection, whereas control animals were administered saline as a vehicle treatment. Following 7 days of CCA, there were significant increases in maximal state 3 respiration, accompanied by a decrease in ROS production in IMF mitochondria (P < 0.05), indicating that mitochondrial adaptations were elicited in the stimulated muscle. Notably, whole muscle autophagy flux, as measured by LC3II and p62, was downregulated in response to 3 days of CCA, and further by 7 days of CCA (P < 0.05). In addition, muscle mitochondrial LC3II flux was decreased by 3 days of CCA, indicative of reduced mitophagy. In contrast, the lysosomal system, measured by TFEB and LAMP1 protein levels, was gradually upregulated by CCA, culminating at day 7. Interestingly, the translocation of TFEB into the nucleus in response to CCA was increased at day 3 (P < 0.05). However, this nuclear TFEB was not sustained and subsequently declined back to basal levels. In conclusion, we suggest that chronic exercise can lead to muscle adaptations through a coordinated mechanism, involving a decrease in autophagy/mitophagy flux, combined with an increase in the capacity of the lysosomal system.Support or Funding InformationThis work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

It Does Not Do to Dwell on Single Components and Forget the Importance of Complete Networks: Optimizing an Integrated Hemodynamic Model Derived from Experimental Data

In our previous study, we demonstrated the important role of capillary resistance and venular network geometry on arteriolar blood flow and red blood cell (RBC) distribution in terminal arterioles (TAs). Using arteriolar and corresponding venular networks reconstructed from intravital videomicroscopy (IVVM) data obtained in rat gluteus maximus preparations, as well as mathematical modelling and simulation, we showed that for RBC flow, adding the same resistance to all TAs to represent downstream capillary beds significantly decreased the coefficient of variation of TA RBC flow (CVTA(RBC), standard deviation/mean, n = 8 networks) by 37%, whereas, adding the venular network did not further significantly change CVTA(RBC). However, we found that adding constant resistive elements to the TAs did not significantly decrease the coefficient of variation of TA tube hematocrit, whereas, adding the venular network significantly decreased CVTA(HT) by 20%. Given the need for this network‐oriented approach, we are optimizing our arteriolar network analysis to include as much detail as possible through experimental acquisition and data reconstruction of arterioles and venules, as well as estimation of missing data using theoretical methods. Our goal is to develop an analysis technique that accounts for the interconnectivity of microvascular systems, and that can be applied to networks in a wide range of situations. In our current methods, we reconstructed corresponding arteriolar and venular networks from experimental data, and estimated and applied total capillary resistance for each network, based on the arteriolar network resistance and the relative pressure drop between the arteriolar and capillary sections of the network. The capillary resistance is now distributed to each TA segment according to its diameter, and therefore, variable. We acquired fluorescent streaks for experimental blood flow data in an arteriolar network, which we used to validate flow values predicted by our model. Using the experimental flow data, we also calculated a Murray's law exponent of approximately a=2.8, to which we compared predicted values. For 3 networks, we found a=2.78±0.30 using variable capillary resistance vs. a=1.95±0.17 using constant capillary resistance. Our results, using improved theoretical methods and newly acquired flow data, show that our network‐oriented approach is moving towards more accurately predicting hemodynamic properties of arteriolar networks under normal baseline conditions. We are currently working to extend this approach and apply it to networks under different experimental conditions.Support or Funding InformationThis work was supported by Natural Sciences and Engineering Research Council of Canada (NSERC) Grants R4081A03 (DG) and R4218A03 (DNJ).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Attenuation of High Glucose/High Insulin‐Induced Muscle Insulin Resistance by Rosemary Extract

Insulin is a key hormone affecting metabolism and plays a major role in the regulation of glucose homeostasis. Skeletal muscle accounts for ~80% of postprandial glucose disposal and is thus the major organ of glucose uptake. Insulin increases muscle glucose uptake by increasing the translocation of intracellularly stored GLUT4 glucose transporters to the plasma membrane through the phosphatidylinositol‐3 kinase (PI3K)/Akt signaling pathway. Impaired PI3K/Akt signaling is associated with insulin resistance (IR) in skeletal muscle, leading to chronically elevated blood glucose levels and followed by a compensatory rise in insulin levels. The elevated glucose and insulin levels, in turn, exacerbate IR. Polyphenols are phytochemicals derived from natural plant sources that were found to have antioxidant, anti‐inflammatory, anti‐cancer and anti‐diabetic effects.Rosemary extract (RE), rich in polyphenols, contains carnosic acid (CA), carnosol (COH) and rosmarinic acid (RA), which have been shown to counteract insulin resistance in both in vitro and in vivo animal models. However, the mechanisms involved are not known. Therefore, the aim of this study is to investigate the effects of RE on high glucose (HG)/high insulin (HI)‐induced skeletal muscle insulin resistance and the molecular mechanisms involved. Glucose uptake was assessed using [3 H]‐2‐deoxy‐d‐glucose. Total and phosphorylated levels of Akt and IRS‐1 were measured by immunoblotting. Exposure of L6 myotubes to 25mM glucose/100nM insulin for 24 h, to mimic hyperglycemia/hyperinsulinemia, abolished the acute insulin‐stimulated glucose uptake (I: 180±10.43, HG/HI + I: 108 % of basal). In addition, HG/HI attenuated the insulin‐stimulated Akt phosphorylation, while increased IRS‐1 Ser 636/639 phosphorylation indicating insulin resistance. Importantly, treatment with RE (5 μg/ml, 24 h) significantly restored the insulin‐stimulated glucose uptake (HG/HI + RE + I: 184%). Our data indicate a potential of RE to counteract muscle insulin resistance. The focus of our research is to investigate the mechanism involved in mediating this effect of RE.Support or Funding InformationSupported by a Natural Sciences and Engineering Research Council of Canada (NSERC) grant to ETThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Consequences of Cytochrome c Oxidase Assembly Defects for the Yeast Stationary Phase

Functional assembly of cytochrome c oxidase (COX) is essential for an intact mitochondrial respiratory chain, although the consequences of a loss of assembled COX at yeast stationary phase remain largely unexplored. Stationary phase cultures are a good model for terminally differentiated cells in humans, such as neurons. Our goal is to define the physiological changes in mitochondrial respiration and oxidative stress between exponential and stationary phases in a respiratory competent strain and a set of COX assembly mutants with defects in a variety of aspects related to enzyme assembly. These results further our understanding of mitochondrial changes in terminally differentiated cells and aging cells. In this study, we show that a wild‐type respiratory competent yeast strain at stationary phase is characterized by a decreased oxidative capacity, as seen by a reduction in the amount of assembled COX, which is supported by a decrease in protein levels of several COX assembly factors. Wild‐type cells also have a disrupted mitochondrial reticulum during stationary phase. Loss of assembled COX results in the decreased abundance of many mitochondrial proteins at stationary phase, which we show is likely due to decreased membrane potential and changes in mitophagy. In addition to an altered mitochondrial proteome, COX assembly mutants display unexpected changes in markers of cellular oxidative stress at stationary phase. Specifically, differences in distribution of Sod1 between exponential and stationary phases give insight on location of reactive oxygen species (ROS) in the cell. Our results suggest that mitochondria may not be a major source of ROS at stationary phase in cells lacking an intact respiratory chain. Overall, we have identified fundamental differences between exponential and stationary phase mitochondria in respiratory competent yeast and have defined two distinct phenotypes, decreased levels of mitochondrial proteins and less mitochondrial oxidative damage, in cells with a defective respiratory chain. These findings suggest that COX deficiencies are associated with broader cellular phenotypes in terminally differentiated cells in humans.Support or Funding InformationNatural Sciences and Engineering Research Council of Canada (NSERC)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

WHICH DESIGN METHODOLOGIES ARE EFFECTIVE TO SUPPORT A CAPSTONE PROJECT IN AEROSPACE DESIGN ENGINEERING?

Abstract – Considering the challenges in the aerospace industry, the NSERC (Natural Sciences and Engineering Research Council of Canada) Chair in Aerospace Design Engineering (NCADE) has launched its own version of a final year undergraduate engineering capstone project at Concordia University. NCADE’s objective is to expose students to the immense complexity of an aircraft design, thereby better meeting the industry needs of newly graduated students. Four design methodologies (i.e., systems engineering – SE, quality function deployment – QFD, theory of inventive problem solving – TRIZ, and environment-based design – EBD) were evaluated in the context of the NCADE project to answer the research question such as "to what extent do these methodologies provide effective support across the activities in the capstone project?" The evaluation was subjective discussing whether the design methodologies support the activities in the project. From the evaluation, it can be concluded that the studied design methodologies perform poorly to support the activities in the capstone project. Therefore, future research should investigate a better support for the capstone project to achieve NCADE’s goals.

Comparison of numerical and experimental results over a naca0025 airfoil undergoing separation

This work was supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC). In addition, the authors acknowledge the support and guidance of Afshin Rahimi during this study.

Optimal parameter regions and the time-dependence of control parameter values for the particle swarm optimization algorithm

The National Research Foundation (NRF) of South Africa (Grant Number 46712) and the Natural Sciences and Engineering Research Council of Canada (NSERC).

The somatogravic illusion during centrifugation: sex differences

Maintaining orientation in an environment with non-Earth gravity (1 g) is critical for an astronaut's operational performance. Such environments present a number of complexities for balance and motion. For example, when an astronaut tilts due to ascending or descending an inclined plane on the moon, the gravity vector will be tilted correctly, but the magnitude will be different from on earth. If this results in a mis-perceived tilt, then that may lead to postural and perceptual errors, such as mis-perceiving the orientation of oneself or the ground plane and corresponding errors in task judgment.

Nested Frobenius extensions of graded superrings

This paper is the result of a research project completed in the context of the first author's Undergraduate Student Research Award from the Natural Sciences and Engineering Research Council of Canada (NSERC). We prove a nesting phenomenon for twisted Frobenius extensions. Namely, suppose $R \subseteq B \subseteq A$ are graded superrings such that $A$ and $B$ are both twisted Frobenius extensions of $R$, $R$ is contained in the center of $A$, and $A$ is projective over $B$. Our main result is that, under these assumptions, $A$ is a twisted Frobenius extension of $B$. This generalizes a result of Pike and the second author, which considered the case where $R$ is a field.

Identification and Association of High-Priority Safety Management System Factors and Accident Precursors for Proactive Safety Assessment and Control

This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) Industrial Research Chair in Construction Engineering and Management (IRCPJ 195558) and Coordination for the Improvement of Higher Education Personnel (CAPES) Ministry of Education of Brazil (Scholarship No. 0393-12-6). Any opinions, findings, conclusions, or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of NSERC and CAPES. Last, the authors thank the anonymous survey respondents for their valuable contributions.

Soundscape fishing: Spatial variability in a low-frequency fish chorus in the southern California kelp forest

The kelp forests off the coast of southern California support a diverse assemblage of fishes, many of which are known to produce sound. Here, the spatial variability of a low-frequency (325–545 Hz) fish chorus recorded at three sites near the kelp forests off La Jolla, California, is described. This chorus dominated the dusk soundscape at all sites in May/June 2015, 2016, and 2017. During these times, spectral levels around 400 Hz increased by approximately 30 dB over a period of 3 h between 19:00 and 22:00 local time. The location of the fish chorus was estimated during each year using beamforming and time difference of arrival (TDOA) techniques on signals recorded by either a two-element 30-m aperture linear seafloor array or an array with four-elements, 20-m aperture in a tetrahedral-shaped configuration. This location was relatively constant during the chorusing each night. Environmental factors such as temperature, macroalgae assemblage and bottom cover, and geological features were investigated as possible drivers of the spatial distribution of the chorus. [Research supported by California Sea Grant (R/HCME-28) and a Natural Sciences and Engineering Research Council of Canada (NSERC) Postgraduate Scholarship-Doctoral (PGS D-3).]

Investigation of Membrane Degradation in Fuel Cells through Nanoscale Electron Tomography

Operational reliability of polymer electrolyte fuel cells (PEFCs) depends on the durability of the components used in its construction. Membrane failure is a life-limiting factor in PEFCs [1] which develops across multiple length scales. Hence, an articulated knowledge congregating known degradation mechanisms at various scales is necessary to draw a complete understanding. The molecular level degradation of perfluorosulfonic acid (PFSA) membranes in PEFCs was found to initiate with OH radicals attacking side chain C-S and α-OCF2 bonds proceeding with further side chain degradation through β-OCF2and culminating in main chain cleavage and unzipping [2]. The molecular level degradation has a profound influence on the membrane macroscale stability [3]. The physical integrity of PFSA ionomer membranes depends on their internal morphology and distribution of hydrophilic and hydrophobic phases [4]. The degradation effects at an intermediate length scale therefore requires in depth study to bridge the molecular and macroscale degradation. Our preliminary research on the mesoscale characterization of membrane degradation was conducted using 2-D electron micrographs and compositional analysis and revealed that membrane failure initiated as local damage and cracks propagated along the direction of low concentration of ion-rich regions as a result of combined chemical/mechanical degradation [4]. However, the 2-D nature of these results constrained the ability to determine hydrophilic and hydrophobic phase volume fractions and their shapes, sizes, and distribution. Therefore, the objective of the present work is to investigate the mesoscale morphology and quantify the effects of PFSA membrane degradation with PEFC operation through tomographic reconstruction of hydrophilic and hydrophobic phases in three dimensions. In this work, standard PFSA ionomer membranes were subjected to a combined chemical and mechanical accelerated stress test (AST) used for rapid benchmarking of in-situ membrane stability [3]. The chemical phase of the AST generates hydroxyl radicals that attack both the side chain and main chain of the polymer, while the mechanical stress generated by humidity cycling accelerates mechanical degradation and failure. Contrast enhanced transmission electron microscopy-tomography (TEM-t) of pristine and degraded PFSA ionomer membranes was carried out to explore the overall morphology and mesoscale features induced by the combined chemical and mechanical degradation process. In order to enhance image contrast, the sulfonic acid end group sites in the membrane were selectively exchanged with Pb ions by soaking it in saturated lead acetate solution. The samples embedded in epoxy resin were sliced to thin films (~70-90 nm) using ultra microtome and collected on a Cu grid for imaging. Nanoscale 3-D image reconstruction followed by Marker-based Watershed segmentation was used to identify weak phase boundaries [5] in the tomograms and thereby reveal the hydrophilic and hydrophobic phase distributions in the membrane. The pristine membrane exhibited a randomly interconnected hydrophilic phase with a scaffolding hydrophobic phase (Figure 1(a)), as expected from morphological theory. The membrane subjected to combined chemical/mechanical degradation was found to have similar overall morphology while containing thinner ionomer bundles and reduced hydrophilic volume fraction with smaller hydrophilic pores in regions with elevated chemical degradation as shown in Figure 1(b). Numerical analysis of the phase-segmented tomograms was performed to achieve detailed quantification of the structural properties, which was not possible with previously applied 2-D approaches and therefore contributes important new information for nanoscale analysis of fuel cell membranes. ACKNOWLEDGMENTS Research funding provided by Automotive Partnership Canada (APC), Natural Sciences and Engineering Research Council of Canada (NSERC) and Ballard Power Systems is gratefully acknowledged. We also thank Ballard Power Systems for experimental support. We thank Chan Lim, FCReL and Trevor Lancon, FEI VSG Inc. for technical support. This work made use of the 4D LABS shared facilities supported by the Canada Foundation for Innovation, British Columbia Knowledge Development Fund, Western Economic Diversification Canada, and Simon Fraser University. REFERENCES: M.P. Rodgers, L.J. Bonville, H.R. Kunz, D.K. Slattery, J. M. Fenton, Chem. Rev. 112 6075 (2012).L. Ghassemzadeh and S. Holdcroft, J. Am. Chem. Soc. 135 8181 (2013).C. Lim, L. Ghassemzadeh, F. Van Hove, M. Lauritzen, J. Kolodziej, G.G. Wang, S. Holdcroft, E. Kjeang, J. Power Sources 257 102 (2014).S. Venkatesan, C. Lim, S. Holdcroft, E. Kjeang, J. Electrochem. Soc. 163 F637 (2016).X. Zhang, F. Jia, S. Luo, G. Liu, Q. Hu, Comput. Meth. Prog. Bio. 113 894 (2014). Figure 1

“One-Pot” Solar Fuels

Chemists have always taken great pride in simplifying a complex multistep chemical synthesis into a single step process, in just one reactor. The motivation for doing so, apart from demonstrating synthetic competency and elegance, is the pursuit of green and sustainable solutions to chemical problems, as single step strategies have the inherent advantage of being atomically, energetically and economically efficient, as well as environmentally friendly and responsible.

Experimental Speedup and Stability Validation for Multi-Step MPC * *M.W. Mehrez, K. Worthmann, and J. Pannek are supported by the Deutsche Forschungsgemeinschaft, Grant WO 2056/1-1 and WO 2056/4-1. M.W. Mehrez, G.K.I. Mann, and R.G. Gosine are supported by Natural Sciences and Engineering Research Council of Canada (NSERC), the Research and Development Corporation (RDC), C-CORE J.I. Clark Chair, and Memorial University

Abstract In this paper, we propose a multi-step model predictive control (MPC) scheme without stabilizing constraints and/or costs. Within this work, a relaxed Lyapunov inequality is employed to verify asymptotic stability of the MPC closed loop. To this end, prior work is adapted to a trajectory based setting. The approach works for shorter prediction horizons in comparison to single-step MPC, but requires to stay in open loop for longer periods of time. We propose a technique to mitigate this drawback during runtime of the algorithm such that we benefit from the inherent robustness of single-step MPC. Then, we present a prime experimental validation of the proposed control scheme on a skid-steering mobile robot and show that the computational effort is significantly reduced.

Predictive Path Following of Mobile Robots without Terminal Stabilizing Constraints * *Authors M.W.M., T.F., and K.W. are supported by the Deutsche Forschungsgemeinschaft, Grants WO 2056/1 and WO 2056/4-1. Authors M.W.M., G.K.I.M., and R.G.G. are supported by Natural Sciences and Engineering Research Council of Canada (NSERC), the Research and Development Corporation (RDC), C-CORE J.I. Clark Chair, and Memorial University of Newfoundland.

Abstract This paper considers model predictive path-following control for differentially driven mobile robots and state-space paths. In contrast to previous works, we analyze stability of model predictive path-following control without stabilizing terminal constraints or terminal costs. To this end, we verify cost controllability assumptions and compute bounds on the stabilizing horizon length. Finally, we draw upon simulations to verify our stability results.

Tensor Factorization based Estimates of Parallel Wiener Hammerstein Models * *Supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) through grant RGPIN/06464-2015 and the Fund for Scientic Research (FWO- Vlaanderen), by the Flemish Government (Methusalem), the Belgian Government through the Inter-university Poles of Attraction (IAP VII) Program, by the ERC Advanced Grant SNLSID under contract 320378 and

Abstract Factoring the third-order Volterra kernel of a Wiener-Hammerstein model to recover the impulse responses of its two constituent linear systems is a common example in the multilinear algebra literature. Since recent progress in regularization-based system identification has enabled the practical estimation of the third-order Volterra kernel, these tensor factorization based approaches have become attractive. We extend one of these Wiener-Hammerstein factorization methods to the case of the Parallel Wiener-Hammerstein model, since, unlike the WH model, this structure is a universal approximator for Volterra systems. The efficacy of the method is demonstrated using numerical simulations.

A comprehensive revisit of the ρ meson with improved Monte-Carlo based QCD sum rules**Supported by NSFC (11175153, 11205093, 11347020), Open Foundation of the Most Important Subjects of Zhejiang Province, and K. C. Wong Magna Fund in Ningbo University, TGS is Supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), Z. F. Zhang and Z. R. Huang are

We improve the Monte-Carlo based QCD sum rules by introducing the rigorous Hölder-inequality-determined sum rule window and a Breit-Wigner type parametrization for the phenomenological spectral function. In this improved sum rule analysis methodology, the sum rule analysis window can be determined without any assumptions on OPE convergence or the QCD continuum. Therefore, an unbiased prediction can be obtained for the phenomenological parameters (the hadronic mass and width etc.). We test the new approach in the ρ meson channel with re-examination and inclusion of αs corrections to dimension-4 condensates in the OPE. We obtain results highly consistent with experimental values. We also discuss the possible extension of this method to some other channels.

0732 NIGHTMARE DISTRESS IS NEGATIVELY CORRELATED WITH REGIONAL CEREBRAL BLOOD FLOW IN FRONTAL AREAS DURING AN IAPS PICTURE-VIEWING TASK

Research has shown that nightmare-related distress (NMD) may better explain the association between nightmares (NM) and psychopathology than NM frequency, but its neurophysiological correlates remain unknown. As part of a brain imaging project exploring the neural correlates of NM in frequent NM sufferers, we investigated if NMD is related to activity in regions hypothesized to be involved in NM production (Nielsen & Levin, 2007). We predicted NMD would correlate with reduced activity (i.e. regional cerebral blood flow) in bilateral prefrontal areas known to down-regulate fear processes governed by the amygdala, i.e., anterior cingulate and medial prefrontal cortices. We also expected NMD to be correlated with reduced activity in the hippocampus and increased activity in the amygdala. We used high resolution 99m-Tc-ECD SPECT imaging to assess regional cerebral blood flow (rCBF) in 21 frequent NM sufferers (NM: 24.9 ± 4.5 yrs (18 W)) during the viewing of negative pictures from the International Affective Picture System (IAPS). We correlated Nightmare Distress Questionnaire (NMDQ) scores with rCBF using a significance threshold of p < .005 (uncorrected) and a cluster threshold of k > 100. Significant negative correlations were observed between NMDQ scores and rCBF in bilateral insula (t = 4.1 and 4.37), bilateral anterior cingulate cortex (t = 4.49 and 5.42), left precentral gyrus (t = 3.54), left medial prefrontal cortex (t = 4.63), and bilateral putamen (t = 4.55 and 4.37). No correlations were observed with the amygdala or hippocampus and no positive correlations were found. Findings partially support our hypothesis. Reduced rCBF in these prefrontal regions involved in affect regulation could reflect a cross-state emotion regulation deficit, which also leads to more distress during dreaming. Our results also reveal reduced activity in regions for which a regulatory role in affective response during dreaming is unclear (insula, putamen), but for which research has demonstrated anatomical and/or functional alterations in PTSD. Supported by research grants from the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fonds de recherche Québec-Santé (FRQS).