329 research outputs found
The amoebal MAP kinase response to Legionella pneumophila is regulated by DupA
Get PDFThe amoeba Dictyostelium discoideum can support replication of Legionella pneumophila. Here we identify the dupA gene, encoding a putative tyrosine kinase/dual-specificity phosphatase, in a screen for D. discoideum mutants altered in allowing L. pneumophila intracellular replication. Inactivation of dupA resulted in depressed L. pneumophila growth and sustained hyperphosphorylation of the amoebal MAP kinase ERK1, consistent with loss of a phosphatase activity. Bacterial challenge of wild-type amoebae induced dupA expression and resulted in transiently increased ERK1 phosphorylation, suggesting that dupA and ERK1 are part of a response to bacteria. Indeed, over 500 of the genes misregulated in the dupA(-) mutant were regulated in response to L. pneumophila infection, including some thought to have immune-like functions. MAP kinase phosphatases are known to be highly upregulated in macrophages challenged with L. pneumophila. Thus, DupA may regulate a MAP kinase response to bacteria that is conserved from amoebae to mammals
Addressing the Verification Challenge of Agile Hardware Methodologies
No full text144 pagesThe slowdown of Moore's Law and the breakdown of Dennard scaling have driven computer architects towards more specialized hardware designs to meet the growing performance and energy efficiency demands. Such specialized hardware designs tend to have high non-recurring engineering (NRE) costs that hinder the research and development of promising hardware systems. The recent rise of agile hardware design methodologies addresses the high NRE costs by promoting the reuse of hardware designs and applying state-of-the-art software design and testing practices to hardware design. Unfortunately, agile hardware methodologies also face unique verification challenges in the hardware development process. In this thesis, I identify and address key verification challenges in agile hardware methodologies. First, I address the verification challenges in dynamic HDLs. Modern HDLs embedded in dynamically typed programming languages facilitate the composition of statically typed hardware instances and dynamically typed test harnesses. However, existing dynamic HDLs suffer from the lack of early-in-design-cycle and complete safety guarantees for mixed-typed compositions and low simulation performance. I propose GT-HDL, an embedded HDL that leverage a combination of optional type checkers, guarded generator parameters, and type-based simulation optimizations to improve simulation performance of dynamic HDLs without compromising safety. Second, I address the verification challenges in generator creation. Recent HDLs heavily rely on parametrized and sophisticated hardware generators to achieve and maximize design reuse. However, it is challenging to verify the correctness of the hardware generators across the entire parameter space. To systematically and statically verify generator properties over a large parameter space, I propose symbolic elaboration, a static analysis technique based on satisfiability modulo theory (SMT) solving. Symbolic elaboration targets a synthesizable subset of HDL syntax and translates generator properties into integer constraints that can be solved by SMT solvers. Third, I overcome the verification challenges in instance composition. Latency-insensitive (LI) interfaces are critical to instance composition in agile hardware because they enable modular and composable hardware designs. However, it is challenging to verify the correctness of the LI interface handshake logic using dynamic verification techniques. I propose a formal verification solution to automatically verify hardware designs with LI interfaces that also generates counter example waveforms to debug LI handshake issues. Finally, I address the verification challenges in co-simulation. Modern HDLs used in agile hardware are typically embedded in a general-purpose host programming language. To maximize verification productivity, designers ideally should iterate on the target design using native simulations before generating RTL in a prototyping language such as Verilog. However, it is challenging to co-simulate the generated Verilog RTL and the test bench in the host language due to semantic gap between the host and the prototyping languages. To overcome this limitation, I propose seamless co-simulation based on a translation-import mechanism. I implement the translation-import mechanism in the PyMTL3 framework and demonstrate how it can improve verification productivity by reusing one test bench for both native simulation and co-simulation. In addition to the proposed solutions to verification challenges, I also present a coarse-grain reconfigurable array (CGRA) chip tape-out case study in GlobalFoundries 14nm technology. This case study demonstrates how the proposed solutions in this thesis can be integrated into an ASIC prototyping workflow and contribute to productive design and testing of the target hardware
The degradation effects of pyrolysis liquids on metals, plastics and elastomers
No full textgrantor:
University of TorontoA study has been conducted to determine the effect of wood pyrolysis fuels on the degradation of specific metal alloys and polymeric materials. Wood pyrolysis fuel has good combustion characteristics but is compositionally different from conventional diesel fuel. This difference requires that materials in contact with these fuels be tested for compatibility. Three types of pyrolysis fuels and blended fuels were tested for compatibility with a variety of metal alloys and polymeric materials. These tests revealed that stainless steels, such as type 430, 304L, 316L and 20Mo4 with more than 12% chromium, had corrosion rates of less than 0.15 mm/y and are suitable for use with all the fuels tested. Type 422, low chromium alloy steel, was found to be highly susceptible to the pyrolysis fuels at high temperature 80°C. In the blended fuel, at all ranges of test temperatures and in pyrolysis fuel at ambient temperature, the alloy showed good resistance. The polymeric materials showed a wide range of corrosion properties in the fuels tested. Details of the material degradation are discussed.M.A.Sc
The degradation effects of pyrolysis liquids on metals, plastics and elastomers
Get PDFgrantor:
University of TorontoA study has been conducted to determine the effect of wood pyrolysis fuels on the degradation of specific metal alloys and polymeric materials. Wood pyrolysis fuel has good combustion characteristics but is compositionally different from conventional diesel fuel. This difference requires that materials in contact with these fuels be tested for compatibility. Three types of pyrolysis fuels and blended fuels were tested for compatibility with a variety of metal alloys and polymeric materials. These tests revealed that stainless steels, such as type 430, 304L, 316L and 20Mo4 with more than 12% chromium, had corrosion rates of less than 0.15 mm/y and are suitable for use with all the fuels tested. Type 422, low chromium alloy steel, was found to be highly susceptible to the pyrolysis fuels at high temperature 80°C. In the blended fuel, at all ranges of test temperatures and in pyrolysis fuel at ambient temperature, the alloy showed good resistance. The polymeric materials showed a wide range of corrosion properties in the fuels tested. Details of the material degradation are discussed.M.A.Sc
Research Progress on the relationship between long chain noncoding RNA and cardiovascular disease
Get PDFLong non coding RNA (lncrna) is a highly conserved non coding RNA (ncRNA) with a length of more than 200 nucleotides. Studies have found that lncrna is closely related to transcriptional regulation, post transcriptional regulation and apparent regulation, and thus participates in the regulation of cardiovascular physiology and pathophysiology. This article summarizes the current biological characteristics of circulating lncrna, the value of lncrna as a potential biomarker of cardiovascular diseases and the future prospects of therapeutic methods
Recent advances in modeling the vulnerability of transportation networks\ud \ud
No full textIt is well known that, for major infrastructure networks such as electricity, gas, railway, road, and urban water networks, disruptions at one point have a knock on effect throughout the network. There is an impressive amount of individual research projects examining the vulnerability of critical infrastructure network. However, there is little understanding of the totality of the contribution made by these projects and their interrelationships. This makes their review a difficult process for both new and existing researchers in the field. To address this issue, a two-step literature review process is used, to provide an overview of the vulnerability of the transportation network in terms of four main themes - research objective, transportation mode, disruption scenario and vulnerability indicator –involving the analysis of related articles from 2001 to 2013. Two limitations of existing research are identified: (1) the limited amount of studies relating to multi-layer transportation network vulnerability analysis, and (2) the lack of evaluation methods to explore the relationship between structure vulnerability and dynamical functional vulnerability. In addition to indicating that more attention needs to be paid to these two aspects in future, the analysis provides a new avenue for the discovery of knowledge, as well as an improved understanding of transportation network vulnerability
Online Newspaper Quality Factors: The impact of Gender, Age, and Skill Level
Get PDFThere has been a proliferation of online newspapers over recent years. Despite this, or perhaps because of it, some quality problems remain. Based on a two-factor model of hygiene and motivator factors, this paper examines quality for online newspapers giving attention to differences across gender, age, and computer skill level. Hygiene factors are essential requirements whose absence causes dissatisfaction, while motivators are desirable elements that add value and increase user satisfaction. This paper presents findings from an empirical study of 84 web users. Results show that hygiene factors for our respondents were Timeliness, Content Attractiveness, Content Coverage, Usefulness, and Navigation, while motivators were Writing Style, Layout, Archives, Services, Interactivity, and use of Multimedia. Four factors were borderline: Journalism Ethics, Ease of Use, Front Page & Headlines, and Locating Information. However, the research reveals some differences in perception of factors across gender, age, and computer skill levels, and further research is recommended to investigate these further
Online newspapers: the impact of culture, sex, and age on the perceived importance of specified quality factors
No full textThere has been a proliferation of online newspapers over recent years. Despite this, or perhaps because of it, factors affecting the quality of online newspapers remain only partially understood. Based on a two-factor model of hygiene and motivator factors, this paper examines quality for online newspapers giving attention to differences across culture, sex, and age. Hygiene factors are essential requirements whose absence causes dissatisfaction, while motivators are desirable elements that add value and increase user satisfaction. The paper presents findings from an empirical study of eighty-four Web users. Results show that hygiene factors for our respondents were: Timeliness, Content attractiveness, Content coverage, Usefulness, and Navigation, while motivators were: Writing style, Layout, Archives, Services, Interactivity, and Multimedia presentation. Four factors were borderline: Journalism ethics, Ease of use, Front page and headlines, and Locating information. However, the research reveals some differences in classification of factors across culture, sex, and age
Honeycomb Borophene Fragment Stabilized in Polyanionic Sandwich Lithium Salt: A New Type of Two-Dimensional Material with Superconductivity
No full textFor
seeking new types of two-dimensional (2D) materials based on
honeycomb borophene, honeycomb borophene fragments stabilized by Li
atoms in sandwich molecules are found theoretically. This is based
on our understanding on the hexagonal B6 ring with two-electron
deficiency and Li atoms as suitable electron donors. In these sandwich
molecules, each hexagonal B6 ring unit of honeycomb borophene
fragments is sandwiched between two Li atoms, forming stable sandwich
lithium salts due to electron transfer from Li atoms to the borophene
fragment. In the sandwich lithium salts, the middle planar layer of
honeycomb borophene fragment polyanions is sandwiched between two
Li+ layers. Owing to the large size effect, the lithium
salt (7Li)7+B2414–(7Li)7+ including the planar polyanion sheet B2414– with a high valence of −14 can serve as an
electron reservoir unusually exhibiting two different behaviors of
the electron donor and electron acceptor. Furthermore, material property
calculations show that this 2D sandwich lithium salt (Li2B2 sheet) is demonstrated to be thermally and mechanically
stable. Remarkably, the Li2B2 sheet is not only
a metal 2D material with a Dirac cone but also an intrinsic superconductor
with the superconducting transition temperature Tc ≈ 6.2 K. This work provides a new potential two-dimensional
material for practical application
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