2,349 research outputs found
A multimodal network design problem for domestic container transportation with short sea shipping
With the growing importance of logistic in a green and environmental friendly way, it is widely accepted that short sea shipping (SSS) is a mean to divert the freight traffic from congested corridor in local communities as well as to reduce environmental costs. It can also relieve the problem of traffic congestion and investment on road construction and maintenance. This paper considers a multimodal transportation model for domestic container cargos, in which the flow of container cargos moving between foreign seaports and domestic cities can be transported via domestic seaports using SSS and inland by truck. We propose a two-level strategy in evaluating the various government policies to encourage or regulate the usage of SSS. While the objective of the freight carriers is to minimize its transportation cost, the government could internalize the external cost and invest on the transportation network with considering the cost to the society. A case study with the Taiwan network is performed to illustrate the benefit and performance of the model.postprintThe 12th World Conference on Transport Research (WCTR), Lisbon, Portugal, 11-15 July 2010
Rapid identification of the medicinal plant Taraxacum formosanum and distinguishing of this plant from its adulterants by ribosomal DNA internal transcribed spacer (ITS) based DNA barcode
Original identification of medicinal plants is essential for quality control. In this study, the internal transcribed spacer 2 (ITS2) nuclear ribosomal DNA served as a DNA barcode and was amplified by allele-specific PCR. This approach was exploited to differentiate Taraxacum formosanum from five related adulterants. Using a set of designed PCR primers, a highly specific 223 bp PCR product of T. formosanum was successfully amplified by PCR. However, no similar DNA fragment was amplified from any of the other adulterants. This indicates that, our allele specific primers have high specificity and can accurately discriminate T. formosanum from its adulterant plants.Key words: Medicinal plant, polymerase chain reaction (PCR), authentication, Taraxacum formosanum, traditional Chinese medicinal, internal transcribed spacers 2 (ITS2)
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Thermal Propagation Modelling of Abnormal Heat Generation in Various Battery Cell Locations
With the increasing demand for energy capacity and power density in battery systems, the thermal safety of lithium-ion batteries has become a major challenge for the upcoming decade. The heat transfer during the battery thermal runaway provides insight into thermal propagation. A better understanding of the heat exchange process improves a safer design and enhances battery thermal management performance. This work proposes a three-dimensional thermal model for the battery pack simulation by applying an in-house model to study the internal battery thermal propagation effect under the computational fluid dynamics (CFD) simulation framework. The simulation results were validated with the experimental data. The detailed temperature distribution and heat transfer behaviour were simulated and analyzed. The thermal behaviour and cooling performance were compared by changing the abnormal heat generation locations inside the battery pack. The results indicated that various abnormal heat locations disperse heat to the surrounding coolant and other cells. According to the current battery pack setups, the maximum temperature of Row 2 cases can be increased by 2.93%, and the temperature difference was also increased. Overall, a new analytical approach has been demonstrated to investigate several stipulating battery thermal propagation scenarios for enhancing battery thermal performances.Australian Research Council (ARC Industrial Transformation Training Centre IC170100032) and the Australian Government Research Training Program Scholarship
The Effect of Interface Texture on Exchange Biasing in Ni80Fe20/Ir20Mn80System
Exchange-biasing phenomenon can induce an evident unidirectional hysteresis loop shift by spin coupling effect in the ferromagnetic (FM)/antiferromagnetic (AFM) interface which can be applied in magnetoresistance random access memory (MRAM) and recording-head applications. However, magnetic properties are the most important to AFM texturing. In this work, top-configuration exchange-biasing NiFe/IrMn(x Å) systems have been investigated with three different conditions. From the high-resolution cross-sectional transmission electron microscopy (HR X-TEM) and X-ray diffraction results, we conclude that the IrMn (111) texture plays an important role in exchange-biasing field (Hex) and interfacial exchange energy (Jk).HexandJktend to saturate when the IrMn thickness increases. Moreover, the coercivity (Hc) dependence on IrMn thickness is explained based on the coupling or decoupling effect between the spins of the NiFe and IrMn layers near the NiFe/IrMn interface. In this work, the optimal values forHexandJkare 115 Oe and 0.062 erg/cm2, respectively
Chemotactic response and adaptation dynamics in Escherichia coli
Adaptation of the chemotaxis sensory pathway of the bacterium Escherichia
coli is integral for detecting chemicals over a wide range of background
concentrations, ultimately allowing cells to swim towards sources of attractant
and away from repellents. Its biochemical mechanism based on methylation and
demethylation of chemoreceptors has long been known. Despite the importance of
adaptation for cell memory and behavior, the dynamics of adaptation are
difficult to reconcile with current models of precise adaptation. Here, we
follow time courses of signaling in response to concentration step changes of
attractant using in vivo fluorescence resonance energy transfer measurements.
Specifically, we use a condensed representation of adaptation time courses for
efficient evaluation of different adaptation models. To quantitatively explain
the data, we finally develop a dynamic model for signaling and adaptation based
on the attractant flow in the experiment, signaling by cooperative receptor
complexes, and multiple layers of feedback regulation for adaptation. We
experimentally confirm the predicted effects of changing the enzyme-expression
level and bypassing the negative feedback for demethylation. Our data analysis
suggests significant imprecision in adaptation for large additions.
Furthermore, our model predicts highly regulated, ultrafast adaptation in
response to removal of attractant, which may be useful for fast reorientation
of the cell and noise reduction in adaptation.Comment: accepted for publication in PLoS Computational Biology; manuscript
(19 pages, 5 figures) and supplementary information; added additional
clarification on alternative adaptation models in supplementary informatio
Oxidative damages in tubular epithelial cells in IgA nephropathy: role of crosstalk between angiotensin II and aldosterone
<p>Abstract</p> <p>Background</p> <p>Inhibition of the renin-angiotensin-aldosterone system (RAAS) slows down the progression of chronic renal diseases (CKD) including IgA nephropathy (IgAN). Herein, we studied the pathogenetic roles of aldosterone (Aldo) in IgAN.</p> <p>Methods</p> <p>Human mesangial cells (HMC) was activated with polymeric IgA (pIgA) from IgAN patients and the effects on the expression of RAAS components and TGF-β synthesis examined. To study the roles of RAAS in the glomerulotubular communication, proximal tubular epithelial cells (PTEC) was cultured with conditioned medium from pIgA-activated HMC with eplerenone or PD123319, the associated apoptotic event was measured by the generation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and reactive oxygen species (ROS).</p> <p>Results</p> <p>Polymeric IgA up-regulated the Aldo synthesis and aldosterone synthase expression by HMC. The release of TGF-β by HMC was up-regulated synergistically by AngII and Aldo and this was inhibited by incubation of HMC with losartan plus eplerenone. Cultured PTEC express the mineralocorticoid receptor, but not synthesizing aldosterone. Apoptosis, demonstrated by cleaved PARP expression and caspase 3 activity, was induced in PTEC activated by conditioned medium prepared from HMC cultured with pIgA from IgAN patients. This apoptotic event was associated with increased generation of NADPH oxidase and ROS. Pre-incubation of PTEC with PD123319 and eplerenone achieved complete inhibition of PTEC apoptosis.</p> <p>Conclusions</p> <p>Our data suggest that AngII and Aldo, released by pIgA activated HMC, served as mediators for inducing apoptosis of PTEC in glomerulo-tubular communications. Crosstalk between AngII and Aldo could participate in determining the tubular pathology of IgAN.</p
Fabrication and verification of conjugated AuNP-antibody nanoprobe for sensitivity improvement in electrochemical biosensors
Abstract This study was designed to obtain covalently coupled conjugates as means for achieving higher stability and better coverage of the AuNPs by antibodies on the particle surface suitable for sensor performance enhancement. Starting by using a modified protocol, colloid gold solution, with mean AuNP core size of ~6 nm was synthesized. The protocol used for conjugation of AuNPs to osteocalcin antibody in this study relies on covalent and electrostatic attractions between constituents. Varieties of conjugates with varying combinations of crosslinkers and different concentrations were successfully synthesized. The obtained products were characterized and their properties were studied to determine the best candidate in sense of antibody - antigen reactivity. Using AuNP-GSH-NHS-Ab combination (1:1:1), the tertiary structure of the protein was maintained and thus the antibody remained functional in the future steps. This one-pot method provided a simple method for covalently coupling antibodies on the particle surface while keeping their functionality intact. The AuNP content of the solution also accelerated electron transfer rate and thus amplifies the detection signal. With the developed and discussed technique herein, a simple solution is modeled to be used for measuring serum levels of biomarkers in single and/or multiplexed sensor systems
Lyotropic 'hairy' TiO2 nanorods
We report the synthesis of the first stable, solution-processable and photocrosslinkable hybrid organic/
inorganic titanium dioxide nanorods as ‘hairy rods’ coated with phosphonate ligands with photoreactive
coumarin groups located in a terminal position. The relationships between the chemical structure of the
diethyl-u-[(7-oxycoumaryl)-n-alkyl]phosphonate ligands on the ligand exchange rate (LER) and the
solubility of the resultant ligand-stabilized titanium dioxide nanorods in organic solvents are elucidated.
These TiO2 nanorods, with an organic ligand coating, are short enough (aspect ratio ¼ 5–8) to be
dissolved in chlorobenzene at high concentrations, but long enough to form lyotropic nematic liquid
crystals. These colloidal solutions are used to deposit a thin, uniform layer of hybrid organic/inorganic
TiO2 nanorods with their long axes in the plane of a flat, smooth substrate through a self-organization
process. Standard photolithographic patterning creates an insoluble dielectric layer of the desired
thickness, smoothness and uniformity and with a dielectric constant of sufficient magnitude, k ¼ 8,
suitable for the fabrication of multilayer, plastic electronic devices using solution-based fabrication
techniques, such as ink-jet printing, used in roll-to-roll manufacturing
Linear, Deterministic, and Order-Invariant Initialization Methods for the K-Means Clustering Algorithm
Over the past five decades, k-means has become the clustering algorithm of
choice in many application domains primarily due to its simplicity, time/space
efficiency, and invariance to the ordering of the data points. Unfortunately,
the algorithm's sensitivity to the initial selection of the cluster centers
remains to be its most serious drawback. Numerous initialization methods have
been proposed to address this drawback. Many of these methods, however, have
time complexity superlinear in the number of data points, which makes them
impractical for large data sets. On the other hand, linear methods are often
random and/or sensitive to the ordering of the data points. These methods are
generally unreliable in that the quality of their results is unpredictable.
Therefore, it is common practice to perform multiple runs of such methods and
take the output of the run that produces the best results. Such a practice,
however, greatly increases the computational requirements of the otherwise
highly efficient k-means algorithm. In this chapter, we investigate the
empirical performance of six linear, deterministic (non-random), and
order-invariant k-means initialization methods on a large and diverse
collection of data sets from the UCI Machine Learning Repository. The results
demonstrate that two relatively unknown hierarchical initialization methods due
to Su and Dy outperform the remaining four methods with respect to two
objective effectiveness criteria. In addition, a recent method due to Erisoglu
et al. performs surprisingly poorly.Comment: 21 pages, 2 figures, 5 tables, Partitional Clustering Algorithms
(Springer, 2014). arXiv admin note: substantial text overlap with
arXiv:1304.7465, arXiv:1209.196
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