Waterloo, Canada

University of Waterloo

uwaterloo.ca/
Waterloo, Canada

University of Waterloo is a public research university whose main campus is located in Waterloo, Ontario, Canada. The main campus is located on 400 hectares of land in Uptown Waterloo, adjacent to Waterloo Park. The university offers a wide variety of academic programs, which is administered by six faculties, and three affiliated university colleges. Waterloo is a member of the U15, a group of research-intensive universities in Canada. Wikipedia.

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The present invention relates to core-shell particles, each particle comprising(A) a core comprising elemental sulfur and(B) a shell, which enwraps core (A), comprising MnO_(2). The present invention further relates to a process for preparing said core-shell particles, to a cathode material for an electrochemical cell comprising said core-shell particles, and to a cathode and an electrochemical cell comprising said cathode materials.


Liu J.,University of Waterloo
TrAC - Trends in Analytical Chemistry | Year: 2014

Fluorescent silver, gold and copper nanoclusters (NCs) have emerged for biosensor development. Compared to semiconductor quantum dots, there is less concern about the toxicity of metal NCs, which can be more easily conjugated to biopolymers. These NCs need a stabilizing ligand. Many polymers, proteins and nucleic acids stabilize NCs, and many DNA sequences produce highly-fluorescent NCs. Coupling these DNA stabilizers with other sequences, such as aptamers, has generated a large number of biosensors.We summarize the synthesis of DNA and nucleotide-templated NCs; and, we discuss their chemical interactions. We briefly review properties of NCs, such as fluorescence quantum yield, emission wavelength and lifetime, structure and photostability.We categorize sensor-design strategies using these NCs into:. (1)fluorescence de-quenching;(2)generation of templating DNA sequences to produce NCs;(3)change of nearby environment; and,(4)reacting with heavy metal ions or other quenchers.Finally, we discuss future trends. © 2014 Elsevier Ltd.


Lamb K.G.,University of Waterloo
Annual Review of Fluid Mechanics | Year: 2014

Internal waves are important physical phenomena on the continental shelf/slope. They are often very energetic, and their breaking provides an important dissipation and mixing mechanism, with implications for biological productivity and sediment transport. Internal waves appear in a variety of forms and can break in a variety of ways. A consequence of their dispersion properties is the breaking of waves reflecting from, or being generated at, near-critical slopes. Breaking mechanisms associated with internal solitary waves include bottom boundary layer instabilities, shear instabilities in the interior of the water column, and wave overturning as they shoal. Shoaling can result in the formation of waves with trapped cores either at the surface or at the bottom. Theoretical, numerical, and laboratory studies have largely focused on simple geometries, whereas recent work has shown that the situation in the ocean is often much more complicated because of more complex geometries and the presence of a full hierarchy of fluid motions. Copyright © 2014 by Annual Reviews. All rights reserved.


Burkov A.A.,University of Waterloo
Physical Review Letters | Year: 2014

We present a theory of the anomalous Hall effect (AHE) in a doped Weyl semimetal, or Weyl metal, including both intrinsic and extrinsic (impurity scattering) contributions. We demonstrate that a Weyl metal is distinguished from an ordinary ferromagnetic metal by the absence of the extrinsic and the Fermi surface part of the intrinsic contributions to the AHE, as long as the Fermi energy is sufficiently close to the Weyl nodes. The AHE in a Weyl metal is thus shown to be a purely intrinsic, universal property, fully determined by the location of the Weyl nodes in the first Brillouin zone. © 2014 American Physical Society.


Lynch M.D.J.,University of Waterloo | Neufeld J.D.,University of Waterloo
Nature Reviews Microbiology | Year: 2015

The profound influence of microorganisms on human life and global biogeochemical cycles underlines the value of studying the biogeography of microorganisms, exploring microbial genomes and expanding our understanding of most microbial species on Earth: that is, those present at low relative abundance. The detection and subsequent analysis of low-abundance microbial populations-the 'rare biosphere'-have demonstrated the persistence, population dynamics, dispersion and predation of these microbial species. We discuss the ecology of rare microbial populations, and highlight molecular and computational methods for targeting taxonomic 'blind spots' within the rare biosphere of complex microbial communities. © 2015 Macmillan Publishers Limited.


Burkov A.A.,University of Waterloo
Physical Review Letters | Year: 2014

We present a microscopic theory of diffusive magnetotransport in Weyl metals and clarify its relation to the chiral anomaly. We derive coupled diffusion equations for the total and axial charge densities and show that the chiral anomaly manifests as a magnetic-field-induced coupling between them. We demonstrate that a universal experimentally observable consequence of this coupling in magnetotransport in Weyl metals is a quadratic negative magnetoresistance, which will dominate all other contributions to magnetoresistance under certain conditions. © 2014 American Physical Society.


Evers S.,University of Waterloo | Nazar L.F.,University of Waterloo
Accounts of Chemical Research | Year: 2013

The goal of replacing combustion engines or reducing their use presents a daunting problem for society. Current lithium-ion technologies provide a stepping stone for this dramatic but inevitable change. However, the theoretical gravimetric capacity (∼300 mA h g-1) is too low to overcome the problems of limited range in electric vehicles, and their cost is too high to sustain the commercial viability of electrified transportation. Sulfur is the one of the most promising next generation cathode materials. Since the 1960s, researchers have studied sulfur as a cathode, but only recently have great strides been made in preparing viable composites that can be used commercially. Sulfur batteries implement inexpensive, earth-abundant elements at the cathode while offering up to a five-fold increase in energy density compared with present Li-ion batteries.Over the past few years, researchers have come closer to solving the challenges associated with the sulfur cathode. Using carbon or conducting polymers, researchers have wired up sulfur, an excellent insulator, successfully. These conductive hosts also function to encapsulate the active sulfur mass upon reduction/oxidation when highly soluble lithium polysulfides are formed. These soluble discharge products remain a crux of the Li-S cell and need to be contained in order to increase cycle life and capacity retention. The use of mesoporous carbons and tailored designs featuring porous carbon hollow spheres have led to highly stable discharge capacities greater than 900 mA h g-1 over 100 cycles. In an attempt to fully limit polysulfide dissolution, methods that rely on coating carbon/sulfur composites with polymers have led to surprisingly stable capacities (∼90% of initial capacity retained). Additives will also play an important role in sulfur electrode design. For example, small fractions (> 3 wt%) of porous silica or titania effectively act as polysulfide reservoirs, decreasing their concentration in the electrolyte and leading to a higher utilization of sulfur and increased capacities. © 2012 American Chemical Society.


Ward O.P.,University of Waterloo
Biotechnology Advances | Year: 2012

The initial focus of recombinant protein production by filamentous fungi related to exploiting the extraordinary extracellular enzyme synthesis and secretion machinery of industrial strains, including Aspergillus, Trichoderma, Penicillium and Rhizopus species, was to produce single recombinant protein products. An early recognized disadvantage of filamentous fungi as hosts of recombinant proteins was their common ability to produce homologous proteases which could degrade the heterologous protein product and strategies to prevent proteolysis have met with some limited success. It was also recognized that the protein glycosylation patterns in filamentous fungi and in mammals were quite different, such that filamentous fungi are likely not to be the most suitable microbial hosts for production of recombinant human glycoproteins for therapeutic use. By combining the experience gained from production of single recombinant proteins with new scientific information being generated through genomics and proteomics research, biotechnologists are now poised to extend the biomanufacturing capabilities of recombinant filamentous fungi by enabling them to express genes encoding multiple proteins, including, for example, new biosynthetic pathways for production of new primary or secondary metabolites. It is recognized that filamentous fungi, most species of which have not yet been isolated, represent an enormously diverse source of novel biosynthetic pathways, and that the natural fungal host harboring a valuable biosynthesis pathway may often not be the most suitable organism for biomanufacture purposes. Hence it is expected that substantial effort will be directed to transforming other fungal hosts, non-fungal microbial hosts and indeed non microbial hosts to express some of these novel biosynthetic pathways. But future applications of recombinant expression of proteins will not be confined to biomanufacturing. Opportunities to exploit recombinant technology to unravel the causes of the deleterious impacts of fungi, for example as human, mammalian and plant pathogens, and then to bring forward solutions, is expected to represent a very important future focus of fungal recombinant protein technology. © 2011.


Clapp J.,University of Waterloo
Journal of Peasant Studies | Year: 2014

This paper provides a new perspective on the political implications of intensified financialization in the global food system. There has been a growing recognition of the role of finance in the global food system, in particular the way in which financial markets have become a mode of accumulation for large transnational agribusiness players within the current food regime. This paper highlights a further political implication of agrifood system financialization, namely how it fosters ‘distancing’ in the food system and how that distance shapes the broader context of global food politics. Specifically, the paper advances two interrelated arguments. First, a new kind of distancing has emerged within the global food system as a result of financialization that has (a) increased the number of the number and type of actors involved in global agrifood commodity chains and (b) abstracted food from its physical form into highly complex agricultural commodity derivatives. Second, this distancing has obscured the links between financial actors and food system outcomes in ways that make the political context for opposition to financialization especially challenging. © 2014 Taylor & Francis.


Ferrie C.,University of Waterloo
Reports on Progress in Physics | Year: 2011

This paper comprises a review of both the quasi-probability representations of infinite-dimensional quantum theory (including the Wigner function) and the more recently defined quasi-probability representations of finite-dimensional quantum theory. We focus on both the characteristics and applications of these representations with an emphasis toward quantum information theory. We discuss the recently proposed unification of the set of possible quasi-probability representations via frame theory and then discuss the practical relevance of negativity in such representations as a criteria for quantumness. © 2011 IOP Publishing Ltd.

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