Royal Military College of Canada

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is thatthere is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure flux through the autophagy pathway (i.e., the completeprocess including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defined as increasedautophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in manycases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as forreviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multipleassays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagyrelated protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular assays, we hope to encourage technical innovation in the field.

All digitizing methods, as a general rule, record lines with far more data than is necessary for accurate graphic reproduction or for computer analysis. Two algorithms to reduce the number of points required to represent the line and, if desired, produce caricatures, are presented and compared with the most promising methods so far suggested. Line reduction will form a major part of automated generalization.

An effective technique in locating a source based on intersections of hyperbolic curves defined by the time differences of arrival of a signal received at a number of sensors is proposed. The approach is noniterative and gives an explicit solution. It is an approximate realization of the maximum-likelihood estimator and is shown to attain the Cramer-Rao lower bound near the small error region. Comparisons of performance with existing techniques of beamformer, spherical-interpolation, divide and conquer, and iterative Taylor-series methods are made. The proposed technique performs significantly better than spherical-interpolation, and has a higher noise threshold than divide and conquer before performance breaks away from the Cramer-Rao lower bound. It provides an explicit solution form that is not available in the beamforming and Taylor-series methods. Computational complexity is comparable to spherical-interpolation but substantially less than the Taylor-series method.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoinduced Motions in Azo-Containing PolymersAlmeria Natansohn and Paul RochonView Author Information Department of Chemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada Department of Physics, Royal Military College, Kingston, Ontario, K7K 5L0, Canada Cite this: Chem. Rev. 2002, 102, 11, 4139–4176Publication Date (Web):October 17, 2002Publication History Received26 December 2001Published online17 October 2002Published inissue 1 November 2002https://pubs.acs.org/doi/10.1021/cr970155yhttps://doi.org/10.1021/cr970155yresearch-articleACS PublicationsCopyright © 2002 American Chemical SocietyRequest reuse permissionsArticle Views14023Altmetric-Citations2029LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Azobenzene,Light,Liquid crystals,Liquids,Polymers Get e-Alerts

The surface of an azoaromatic polymer film is optically altered to produce local highly efficient diffraction gratings. The gratings obtained are stable but can be erased by heating the polymer above its glass transition temperature and no permanent damage of the film is observed. Multiple gratings can be simultaneously written and gratings can be overwritten. Atomic force microscopy was used to investigate the gratings produced on the surfaces. Possible mechanisms responsible for the surface alteration are discussed.

The development of autonomous unmanned aerial vehicles (UAVs) is of high interest to many governmental and military organizations around the world. An essential aspect of UAV autonomy is the ability for automatic path planning. In this paper, we use the genetic algorithm (GA) and the particle swarm optimization algorithm (PSO) to cope with the complexity of the problem and compute feasible and quasi-optimal trajectories for fixed wing UAVs in a complex 3D environment, while considering the dynamic properties of the vehicle. The characteristics of the optimal path are represented in the form of a multiobjective cost function that we developed. The paths produced are composed of line segments, circular arcs and vertical helices. We reduce the execution time of our solutions by using the “single-program, multiple-data” parallel programming paradigm and we achieve real-time performance on standard commercial off-the-shelf multicore CPUs. After achieving a quasi-linear speedup of 7.3 on 8 cores and an execution time of 10 s for both algorithms, we conclude that by using a parallel implementation on standard multicore CPUs, real-time path planning for UAVs is possible. Moreover, our rigorous comparison of the two algorithms shows, with statistical significance, that the GA produces superior trajectories to the PSO.

Development of induced anisotropy during shear deformation of plane granular assemblies is inves- tigated by introducing statistical characteristics of fabric and contact forces. The introduced micro-structural parameters are explicitly related to the measure of deviatoric load by considering condi-tions of static equilibrium. Verification of the relationship between parameters of anisotropy, average forces and external loads is presented based on numerical simulation of tests on plane granular assemblies. The physical significance of introduced parameters of microstructure and their evolution during shear deformations is discussed. Le développment de l'anisotropie induite pendant la déformation de cisaillement d'assemblages plans granulaires est examiné grâce à l'introduction de caractécristiques statistiques de la fabrique et des efforts de contact. Les paramétres microstructuraux introduits sont reliés de facon explicite à la mesure du chargement déviatorique en considérant les conditions de I'équilibrestatique. La vèification de la relation entre les paramétres d'anisotropie, les forces moyennes et les chargements externes est présentée sur la base de la simulation numérique d'essais sur des assemblages plans granulaires. On analyse l'importance physique des paramtitres microstructuraux introduits et leur évolution pendant les déformations de cisaillement.

A parametric model predicting the performance of a solid polymer electrolyte, proton exchange membrane (PEM) fuel cell has been developed using a combination of mechanistic and empirical modeling techniques. This paper details the mechanistic model development. Mass transport properties are considered in the mechanistic development via Stefan‐Maxwell equations. Thermodynamic equilibrium potentials are defined using the Nernst equation. Activation overvoltages are defined via a Tafel equation, and internal resistances are defined via the Nernst‐Planck equation, leading to a definition of ohmic overvoltage via an Ohm's law equation. The mechanistic model cannot adequately model fuel cell performance, since several simplifying approximations have been used in order to facilitate model development. Additionally, certain properties likely to be observed in operational fuel cells, such as thermal gradients, have not been considered. Nonetheless, the insights gained from the mechanistic assessment of fuel cell processes were found to give the resulting empirical model a firmer theoretical basis than many of the models presently available in the literature. Correlation of the empirical model to actual experimental data was very good.

A parametric model predicting the performance of a solid polymer electrolyte, proton exchange membrane (PEM) fuel cell has been developed using a combination of mechanistic and empirical modeling techniques. This paper details the empirical analysis which yielded the parametric coefficients employed in the model. A 28 run experiment covering a range of operating currents (50 to 300 ASF), temperatures (328 to 358 K), oxygen partial pressures (0.6 to 3.1 atm abs.) and hydrogen partial pressures (2.0 to 3.1 atm abs.) was conducted. Parametric equations for the activation overvoltage and the internal resistance of the fuel cell were obtained from linear regression. The factors to be employed in the linear regression had been previously determined through a mechanistic analysis of fuel cell processes. Activation overvoltage was modeled as a function of the operating temperature, the product of operating temperature, and the logarithm of the operating current, and the product of operating temperature and the logarithm of the oxygen concentration at the catalyst reaction sites. The internal resistance of the fuel cell was modeled as a function of the operating temperature and the current. Correlation of the empirical model to experimental data was very good. It is anticipated that the mechanistic validity yielded by the coupling of mechanistic and empirical modeling techniques will also allow for accurate predictive capabilities outside of the experimental range.

We present a current catalog of 21 cm H I line sources extracted from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey over ~2800 deg^2 of sky: the α.40 catalog. Covering 40% of the final survey area, the α.40 catalog contains 15,855 sources in the regions 07^h30^m &lt; R.A. &lt; 16^h30^m, +04° &lt; decl. &lt;+16°, and +24° &lt; decl. &lt;+28° and 22^h &lt; R.A. &lt; 03^h, +14° &lt; decl. &lt;+16°, and +24° &lt; decl. &lt; + 32°. Of those, 15,041 are certainly extragalactic, yielding a source density of 5.3 galaxies per deg^2, a factor of 29 improvement over the catalog extracted from the H I Parkes All-Sky Survey. In addition to the source centroid positions, H I line flux densities, recessional velocities, and line widths, the catalog includes the coordinates of the most probable optical counterpart of each H I line detection, and a separate compilation provides a cross-match to identifications given in the photometric and spectroscopic catalogs associated with the Sloan Digital Sky Survey Data Release 7. Fewer than 2% of the extragalactic H I line sources cannot be identified with a feasible optical counterpart; some of those may be rare OH megamasers at 0.16 &lt; z &lt; 0.25. A detailed analysis is presented of the completeness, width-dependent sensitivity function and bias inherent of the α.40 catalog. The impact of survey selection, distance errors, current volume coverage, and local large-scale structure on the derivation of the H I mass function is assessed. While α.40 does not yet provide a completely representative sampling of cosmological volume, derivations of the H I mass function using future data releases from ALFALFA will further improve both statistical and systematic uncertainties.

The wavelet transform is introduced as a powerful tool for monitoring power quality problems generated due to the dynamic performance of industrial plants. The paper presents a multiresolution signal decomposition technique as an efficient method in analyzing transient events. The multiresolution signal decomposition has the ability to detect and localize transient events and furthermore classify different power quality disturbances. It can also be used to distinguish among similar disturbances.

This paper reports grand canonical Monte Carlo computations on the diffuse double layer in an ionic system next to a uniformly charged plane surface. The boundary conditions and the grand canonical techniques are discussed. Calculations were carried out for the 1:1 restricted primitive model at several concentrations and over a range of surface charge densities. The results are compared with the modified Gouy–Chapman theory, and some remarks are also possible with respect to the modified Poisson–Boltzmann and the hypernetted chain approaches. At high concentrations and surface charge densities the counterions are packed closely at the surface and begin to show a layered structure. This results in a large electrostatic potential drop, but only very slight charge oscillations are observed in the solution. None of the theories seems able to describe this behavior.

A nominally-zero-pressure-gradient incompressible boundary layer over a smooth flat plate was simulated for a continuous momentum thickness Reynolds number range of 80 ≤ Re θ ≤ 940. Transition which is completed at approximately Re θ = 750 was triggered by intermittent localized disturbances arising from patches of isotropic turbulence introduced periodically from the free stream at Re θ = 80. Streamwise pressure gradient is quantified with several measures and is demonstrated to be weak. Blasius boundary layer is maintained in the early transitional region of 80 &lt; Re θ &lt; 180 within which the maximum deviation of skin friction from the theoretical solution is less than 1%. Mean and second-order turbulence statistics are compared with classic experimental data, and they constitute a rare DNS dataset for the spatially developing zero-pressure-gradient turbulent flat-plate boundary layer. Our calculations indicate that in the present spatially developing low-Reynolds-number turbulent flat-plate boundary layer, total shear stress mildly overshoots the wall shear stress in the near-wall region of 2–20 wall units with vanishing normal gradient at the wall. Overshoots as high as 10% across a wider percentage of the boundary layer thickness exist in the late transitional region. The former is a residual effect of the latter. The instantaneous flow fields are vividly populated by hairpin vortices. This is the first time that direct evidence (in the form of a solution of the Navier–Stokes equations, obeying the statistical measurements, as opposed to synthetic superposition of the structures) shows such dominance of these structures. Hairpin packets arising from upstream fragmented Λ structures are found to be instrumental in the breakdown of the present boundary layer bypass transition.

Abstract The equation for the sol fraction (s) of a cross-linked polymer network becomes readily tractable when applied to special cases of the generalized distribution function n(u) = C(u/u1)λ-1 exp ( — λu/u1). For values of λ = ∞, 1 and 0 respectively, this function yields the uniform distribution, the exponential distribution and a hypothetical pseudo-random distribution. Assuming that cross-linking and fracture occur at random and in proportion to the radiation dose, simple expressions are derived relating sol fraction to radiation dose (r) for each of the three distributions. The most useful of these is the relation involving the fracture density per unit dose (p0) and the density of cross-linked units per unit dose (q0). s+√s = p0/q0 + 1/q0u1r. This holds strictly for exponential distributions, whether or not main-chain fracture occurs simultaneously with cross-linking, and also holds at high doses for the other distributions considered, providing that cross-linking is accompanied by fracture. This treatment is applied to experimental results on low-density and high-density polyethylenes, polyvinyl acetates, polyvinyl chloride, polypropylene and polyalkyl acrylates. The relevant radiation parameters p0, q0 and the corresponding G values are deduced. It is found, in the case of polyethylene, that q0 is, within experimental error independent of the molecular weight, degree of branching or crystallinity, but is affected by the presence of air. Similar values of q0 are also observed for polyvinyl acetate and polyvinyl chloride.

Three or more base stations (BS) making time-of-arrival measurements of a signal from a mobile station (MS) can locate the MS. However, when some of the measurements are from non-line-of-sight (NLOS) paths, the location errors can be very large. This paper proposes a residual test (RT) that can simultaneously determine the number of line-of-sight (LOS) BS and identify them. Then, localization can proceed with only those LOS BS. The RT works on the principle that when all measurements are LOS, the normalized residuals have a central Chi-Square distribution, versus a noncentral distribution when there is NLOS. The residuals are the squared differences between the estimates and the true position. Normalization by their variances gives a unity variance to the resultant random variables. In simulation studies, for the chosen geometry and NLOS and measurement noise errors, the RT can determine the correct number of LOS-BS over 90% of the time. For four or more BS, where there are at least three LOS-BS, the estimator has variances that are near the Cramer--Rao lower bound.

A series of amorphous azobenzene-containing polymers were cast as thin films and shown to produce both reversible volume diffraction gratings and high-efficiency surface gratings by laser irradiation at an absorbing wavelength. The latter process involves localized mass transport of the polymer chains to a high degree, as atomic force microscopy reveals surface profile depths near that of the original film thickness. A mechanism for this phenomenon is proposed which involves pressure gradients as a driving force, present due to different photochemical behaviors of the azo chromophores at different regions of the interference pattern. The phase addition of the two beams in the interference pattern leads to regions of high trans-cis-trans isomerization by the absorbing azo groups, bordered by regions of low isomerization. As the geometrical isomerization requires free volume in excess of that available in the cast films, the photochemical reaction in these areas produces a laser-induced internal pressure above the yield point of the material. It is proposed that the resulting viscoelastic flow from these high-pressure areas to lower-pressure areas leads to the formation of the regularly spaced sinusoidal surface relief gratings observed by a number of research groups, but previously unexplained. This mechanism of photoinduced viscoelastic flow agrees well with the results of experiments investigating the effect of the polarization state of the interfering writing beams and the photochemical behavior of the chromophore, the free volume requirements of the induced geometric changes, and the viscoelastic flow of the material.

5R4. Mechanics of Composite Structures. - LP Kollar and GS Springer. Cambridge UP, Cambridge, UK. 2003. 480 pp. ISBN 0-521-80165-6. $95.00.Reviewed by M-A Erki (Dept of Civil Eng, Royal Military Col of Canada, PO Box 17000 Station Forces, Kingston ON, K7K 7B4, Canada).This comprehensive book presents traditional topics of structural mechanics that target the topics of interest for designers of aerospace, land, and marine structures, namely plates, beams, and shells, including where appropriate the analyses for their buckling, vibrations, deformations, and displacements. While the topics are familiar to designers using isotropic materials, in this book they are presented for anisotropic composite materials of all types, which are long-fiber composites, short-fiber composites, particulate composites, unidirectional lamina, biaxial weave woven fabric, and triaxial weave woven fabric. Chapter 1 illustrates these materials. It describes the structure of laminate composites and how the individual plies contribute to the laminate behavior. The chapter also defines the various levels of analysis for a structure made of a laminated composite, from the micro (analysis of the matrix and fiber) to macro (analysis of the composite), ending with structural analysis of components, herein plates, beams, and shells. The foundation for all subsequent derivations and analyses in the book are given in Chapter 2. It presents the generalized 3D relationships between displacements and strains and between strains and stresses, via equilibrium equations. The stress-strain relationship is developed first for general anisotropic material, followed by the simplifications that can be made for monoclinic material, orthotropic material, transversely isotropic material, and isotropic material. The differences in analytical approaches for plane strain and plane stress analyses are carefully explained using the specific examples for all these materials for the conditions of free end and built-in ends. The effect of temperature and moisture content on strains and stresses is discussed for both the plane strain and plane stress conditions.A section on boundary conditions and how these are applied to obtain solutions to the equilibrium, stress-strain, and strain displacement equations is given. Continuity conditions between laminated layers that are assumed perfectly bonded are described. Stress and strain transformations using direction cosines and transformation of the stiffness and compliance matrices are discussed for the plane-strain and plane-stress conditions. Finally the strain energy equations are derived, and the Ritz Method is summarized as a solution method for these. The chapter ends with a comprehensive summary of the chapter contents and a numerical example. Chapter 3 discusses the analysis of laminated composites and the contribution of the behavior of individual plies to the overall behavior of the laminate. Stiffness matrices for thin laminates, an example of symmetrical laminate, balanced laminate and orthotropic laminate, isotropic laminate, and quasi-isotropic laminate are illustrated with numerical examples. The next five chapters present the analyses for the basic structural members composed of composite materials, namely thin plates, sandwich plates, solid and thin-walled beams without and with shear deformations, and shells, all with numerical examples as appropriate. Unique considerations for the finite element analysis of composite materials and composite material structures are described in Chapter 9. Chapter 10 discusses failure criteria for the basic types of composite materials, and Chapter 11 summarizes composite material micromechanics. Three valuable appendices give supplementary material of value to the designer. They are the cross-sectional properties of thin-walled composite beams; the buckling loads and natural frequencies of orthotropic beams with shear deformations; and typical composite material properties. Owing to the clarity and breadth of its content, Mechanics of Composite Structures makes a valuable contribution to the field of analysis and design using composite materials. It is well illustrated throughout. Of note, the examples given throughout are truly excellent, because they are both relevant to the development of the concepts presented and practical for designers. The authors have made a special effort to make the book self-contained so that it can be equally suitable as a text for self-study, senior undergraduate, or for a graduate course.

Seafood, including finfish, shellfish, and seaweed, is the largest contributor to arsenic (As) exposure in many human populations. In contrast to the predominance of inorganic As in water and many terrestrial foods, As in marine-derived foods is present primarily in the form of organic compounds. To date, human exposure and toxicological assessments have focused on inorganic As, while organic As has generally been considered to be non-toxic. However, the high concentrations of organic As in seafood, as well as the often complex As speciation, can lead to complications in assessing As exposure from diet. In this report, we evaluate the presence and distribution of organic As species in seafood, and combined with consumption data, address the current capabilities and needs for determining human exposure to these compounds. The analytical approaches and shortcomings for assessing these compounds are reviewed, with a focus on the best practices for characterization and quantitation. Metabolic pathways and toxicology of two important classes of organic arsenicals, arsenolipids and arsenosugars, are examined, as well as individual variability in absorption of these compounds. Although determining health outcomes or assessing a need for regulatory policies for organic As exposure is premature, the extensive consumption of seafood globally, along with the preliminary toxicological profiles of these compounds and their confounding effect on assessing exposure to inorganic As, suggests further investigations and process-level studies on organic As are needed to fill the current gaps in knowledge.

This paper proposes an energy management and control system for laboratory scale microgrid based on hybrid energy resources such as wind, solar, and battery. Power converters and control algorithms have been used along with dedicated energy resources for the efficient operation of the microgrid. The control algorithms are developed to provide power compatibility and energy management between different resources in the microgrid. It provides stable operation of the control in all microgrid subsystems under various power generation and load conditions. The proposed microgrid, based on hybrid energy resources, operates in autonomous mode and has an open architecture platform for testing multiple different control configurations. A real-time control system has been used to operate and validate the hybrid resources in the microgrid experimentally. The proposed laboratory scale microgrid can be used as a benchmark for future research in smart grid applications.

This paper features some of the advances in dielectric-resonator antenna technology at the Communications Research Centre. Several novel elements are presented that offer significant enhancements to parameters such as impedance bandwidth, circular-polarization bandwidth, gain, or coupling to various feed structures. Several linear and planar arrays are also presented, to illustrate the performance of dielectric-resonator antenna elements in the array environment.