584 research outputs found
The application of thermal, catalytic and non-thermal plasma oxidation processes to enhance NO-NOoxidation in the engine exhaust and improve DPF regeneration at lower temperatures
Diesel Particulate Filter (DPF) is believed to be one of the most effective methods and provides an efficient system that traps more than 90% of PM. However, the soot accumulated within the filter requires a regeneration process to recover its performance. Thus, the high oxidation ability of NO-NO increases the interest of applying it in the low temperature regeneration process.
The intention of this thesis is to investigate several possibilities of on-board NO-NO oxidation methods for increasing the NO/NO ratio in the exhaust gas.
These possible oxidation routes incorporate the in-cylinder to the exhaust gas treatment processes. A wide range of operated temperatures are managed by the application of the non-thermal plasma oxidation (NTP) for low temperatures, catalytic oxidation for moderated temperatures and thermal oxidation for high temperatures studied.
The in-cylinder NO oxidation was significantly improved by adding H or the reformed EGR (REGR) to the combustion. The remaining H after the combustion also contributes to the downstream HC-SCR which in turn promotes the NO oxidation.
The thermal and NTP methods in the exhaust treatment cannot adequately achieve a satisfactory NO oxidation result under a single occupied condition. The propane (CH) addition may potentially create useful radicals (HO, RO) within the system and convert a large portion of NO into NO
The Impact of Virtual Environments for Future Electric Powered-Mobility Development Using Human-in-the-Loop: Part A - Fundamental Design and Modelling
The use of virtual tools will be discussed across two complimentary chapters, Part A explores the fundamental concepts of electric vehicle systems modelling and a design procedure for human-in-the-loop virtual environments; Part B demonstrates how this architecture can be applied to assess energy optimization strategies. In Part A, this research investigates the design and implementation of simulation tools used to predict the energy consumption and strategic tool for the development of an electric vehicle. The case study used is an electric prototype race car for Ene-1 GP SUZUKA competition. Engineering effort is re-directed from physical product design, optimisation and validation to digital tools, processes and virtual testing. This virtual platform is characterised by the integration of two different simulation models—mathematical model of the electric vehicle systems represented by Matlab/Simulink, which accounts for the representation of the powertrain performance prediction that taking into account the resistance motion; and a virtual environment represented by Cruden Software, which accounts recreate topography of real world environment in a driving simulator and incorporate human driver behaviour
The Impact of Virtual Environments for Future Electric Powered-Mobility Development Using Human-in-the-Loop: Part B - Virtual Testing and Physical Validation
Electric vehicles are increasing in popularity worldwide, and there have been numerous advances in technology to increase the energy efficiency of the vehicle and reduce the range anxiety for the user. For example, the latest electric vehicle (Tesla model S, equipped by 100kWh battery) available in the market in 2019 is able to drive around 375 miles. However, human behavior such as driving strategy is an important issue that impacts on energy optimization and ultimately vehicle range. Human behavior is rather complex and is difficult to replicate with computer algorithms. Therefore, to fully assess the impact of a particular technology, the interactions between humans, vehicle, and the environment need to be examined simultaneously, through a Human-in-the-Loop approach. In this chapter, the results of investigating a human-in-the-loop test platform, which incorporate human-driving behavior and the vehicle characteristics, are presented. In addition, this chapter analyzes a driving strategy, using a Human-in-the-Loop approach, applied to optimizing the energy usage for an electric vehicle competition
Topological Transitions with an Imaginary Aubry-Andre-Harper Potential
We study one-dimensional lattices with imaginary-valued Aubry-Andre-Harper
(AAH) potentials. Such lattices can host edge states with purely imaginary
eigenenergies, which differ from the edge states of the Hermitian AAH model and
are stabilized by a non-Hermitian particle-hole symmetry. The edge states arise
when the period of the imaginary potential is a multiple of four lattice
constants. They are topological in origin, and can manifest on domain walls
between lattices with different modulation periods and phases, as predicted by
a bulk polarization invariant. Interestingly, the edge states persist and
remain localized even if the real line gap closes. These features can be used
in laser arrays to select topological lasing modes under spatially extended
pumping
Pure curcumin decreases the expression of WT1 by upregulation of miR-15a and miR-16-1 in leukemic cells
<p>Abstract</p> <p>Background</p> <p>Pure curcumin has been reported to down-regulate the expression of WT1 in leukemic cells. However, the molecular mechanism underlying the down-regulation of WT1 by curcumin is not completely delineated. The purpose of this present study is to identify a new miRNA-mediated mechanism which plays an important role in the anti-proliferation effects of curcumin in leukemic cells.</p> <p>Methods</p> <p>K562 and HL-60 cells were treated with different concentrations of curcumin for 24 and 48 hours, the level of miR-15a/16-1 and WT1 were detected by qRT-PCR and Western blotting. WT1 expression and cell proliferation were detected by Western blotting and CCK-8, after curcumin treated-K562 and HL-60 cells were transfected with anti-miR-15a/16-1 oligonucleotides.</p> <p>Results</p> <p>We found that pure curcumin upregulated the expression of miR-15a/16-1 and downregulated the expression of WT1 in leukemic cells and primary acute myeloid leukemia (AML) cells. Overexpression of miR-15a/16-1 deduced the protein level of WT1 in leukemic cells, but downregulation of WT1 by siRNA-WT1 could not increase the expression of miR-15a/16-1 in leukemic cells. These results reveal that curcumin induced-upregulation of miR-15a/16-1 is an early event upstream to downregulation of WT1. Furthermore, anti-miR-15a/16-1 oligonucleotides (AMO) partly reversed the downregulation of WT1 induced by pure curcumin in leukemic cells and AMO promoted the growth of curcumin treated-K562 and HL-60 cells.</p> <p>Conclusion</p> <p>Thus, these data suggest for the first time that pure curcumin downregulated the expression of WT1 partly by upregulating the expression of miR-15a/16-1 in leukemic cells. miR-15a/16-1 mediated WT1 downregulation plays an important role in the anti-proliferation effect of curcumin in leukemic cells.</p
Metal-bonded perovskite lead hydride with phonon-mediated superconductivity up to 46 K under atmospheric pressure
In the search for high-temperature superconductivity in hydrides, a plethora
of multi-hydrogen superconductors have been theoretically predicted, and some
have been synthesized experimentally under ultrahigh pressures of several
hundred GPa. However, the impracticality of these high-pressure methods has
been a persistent issue. In response, we propose a new approach to achieve
high-temperature superconductivity under atmospheric pressure by implanting
hydrogen into lead to create a stable few-hydrogen metal-bonded perovskite,
PbH. This approach diverges from the popular design methodology of
multi-hydrogen covalent high critical temperature () superconductors under
ultrahigh pressure. By solving the anisotropic Migdal-Eliashberg (ME)
equations, we demonstrate that perovskite PbH is a typical phonon-mediated
superconductor with a of 46 K, which is six times higher than that of
bulk Pb (7.22 K) and higher than that of MgB (39 K). The high can be
attributed to the strong electron-phonon coupling (EPC) strength of 2.45, which
arises from hydrogen implantation in lead that induces several high-frequency
optical phonon modes with a relatively large phonon linewidth resulting from H
atom vibration. The metallic-bonding in perovskite PbH not only improves
the structural stability but also guarantees better ductility than the widely
investigated multi-hydrogen, iron-based, and cuprate superconductors. These
results suggest that there is potential for the exploration of new
high-temperature superconductors under atmospheric pressure and may reignite
interest in their experimental synthesis soon.Comment: 6 pages, 4 figure
Multi-Modality Imaging of Atheromatous Plaques in Peripheral Arterial Disease: Integrating Molecular and Imaging Markers
Peripheral artery disease (PAD) is a common and debilitating condition characterized by the narrowing of the limb arteries, primarily due to atherosclerosis. Non-invasive multi-modality imaging approaches using computed tomography (CT), magnetic resonance imaging (MRI), and nuclear imaging have emerged as valuable tools for assessing PAD atheromatous plaques and vessel walls. This review provides an overview of these different imaging techniques, their advantages, limitations, and recent advancements. In addition, this review highlights the importance of molecular markers, including those related to inflammation, endothelial dysfunction, and oxidative stress, in PAD pathophysiology. The potential of integrating molecular and imaging markers for an improved understanding of PAD is also discussed. Despite the promise of this integrative approach, there remain several challenges, including technical limitations in imaging modalities and the need for novel molecular marker discovery and validation. Addressing these challenges and embracing future directions in the field will be essential for maximizing the potential of molecular and imaging markers for improving PAD patient outcomes
Salmonella Outer Protein B Suppresses Colitis Development via Protecting Cell From Necroptosis
Salmonella effectors translocated into epithelial cells contribute to the pathogenesis of infection. They mediate epithelial cell invasion and subsequent intracellular replication. However, their functions in vivo have not been well-identified. In this study, we uncovered a role for Salmonella outer protein B (SopB) in modulating necroptosis to facilitate bacteria escape epithelial cell and spread to systemic sites through a Salmonella-induced colitis model. Mice infected with SopB deleted strain ΔsopB displayed increased severity to colitis, reduced mucin expression and increased bacterial translocation. In vitro study, we found there was an increased goblet cell necroptosis following ΔsopB infection. Consistently, mice infected with ΔsopB had a strong upregulation of mixed lineage kinase domain-like (MLKL) phosphorylation. Deletion of MLKL rescued severity of tissue inflammatory, improved mucin2 expression and abolished the increased bacterial translocation in mice infected with ΔsopB. Intriguingly, the expression of sopB in LS174T cells was downregulated. The temporally regulated SopB expression potentially switched the role from epithelial cell invasion to bacterial transmission. Collectively, these results indicated a role for SopB in modulating the onset of necroptosis to increased bacteria pathogenesis and translocated to systemic sites
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