347 research outputs found
A Methodology to Estimate Real-world Vehicle Fuel Use and Emissions based on Certification Cycle Data
AbstractThis work presents a methodology to estimate vehicle fuel consumption and NOx mass emission rates using only public certification data from individual vehicles. Using on-road data collected from 14 vehicles it was possible to establish trends of fuel use and emissions according with the power demand, using the Vehicle Specific Power methodology, which were further applied to estimate modal fuel consumption and NOx emission rates on Diesel vehicles. Comparing with real-world operation, fuel consumption estimates presented average absolute deviations lower than 10%. Regarding NOx estimates, average absolute deviation is around 22%. With this method it is possible to evaluate an individual vehicle using public data without have to measure it on-road and establishing links between certification and real-world vehicle operation
Analysis of financial indices by means of the windowed Fourier transform
The goal of this study is to analyze the dynamical
properties of financial data series from nineteen worldwide
stock market indices (SMI) during the period 1995–2009.
SMI reveal a complex behavior that can be explored since it
is available a considerable volume of data. In this paper is
applied the window Fourier transform and methods of fractional
calculus. The results reveal classification patterns typical
of fractional order systems
Power law analysis of financial index dynamics
Power law PL and fractional calculus are two faces of phenomena with long memory behavior.
This paper applies PL description to analyze different periods of the business cycle. With such
purpose the evolution of ten important stock market indices DAX, Dow Jones, NASDAQ, Nikkei,
NYSE, S&P500, SSEC, HSI, TWII, and BSE over time is studied. An evolutionary algorithm is
used for the fitting of the PL parameters. It is observed that the PL curve fitting constitutes a good
tool for revealing the signal main characteristics leading to the emergence of the global financial
dynamic evolution
Analysis of stock market indices through multidimensional scaling
We propose a graphical method to visualize possible time-varying correlations between fifteen
stock market values. The method is useful for observing stable or emerging clusters of
stock markets with similar behaviour. The graphs, originated from applying multidimensional
scaling techniques (MDS), may also guide the construction of multivariate econometric
models
Analysis of stock market indices with multidimensional scaling and wavelets
Stock market indices SMIs are important measures of financial and economical performance.
Considerable research efforts during the last years demonstrated that these signals have a chaotic
nature and require sophisticated mathematical tools for analyzing their characteristics. Classical
methods, such as the Fourier transform, reveal considerable limitations in discriminating different
periods of time. This paper studies the dynamics of SMI by combining the wavelet transform
and the multidimensional scaling MDS . Six continuous wavelets are tested for analyzing the
information content of the stock signals. In a first phase, the real Shannon wavelet is adopted for
performing the evaluation of the SMI dynamics, while their comparison is visualized by means of
the MDS. In a second phase, the other wavelets are also tested, and the corresponding MDS plots
are analyzed
Analysis of financial data series using fractional Fourier transform and multidimensional scaling
The goal of this study is the analysis of
the dynamical properties of financial data series from
worldwide stock market indexes during the period
2000–2009. We analyze, under a regional criterium,
ten main indexes at a daily time horizon. The methods
and algorithms that have been explored for the
description of dynamical phenomena become an effective
background in the analysis of economical data.
We start by applying the classical concepts of signal
analysis, fractional Fourier transform, and methods of
fractional calculus. In a second phase we adopt the
multidimensional scaling approach. Stock market indexes
are examples of complex interacting systems for
which a huge amount of data exists. Therefore, these
indexes, viewed from a different perspectives, lead to
new classification patterns
Gold@mesoporous silica nanocarriers for the effective delivery of antibiotics and by-passing of β-lactam resistance
POCI-01-0145-FEDER-007265
PD/BD/142865/2018
CEECIND/00648/2017
UIDB/04077/2020
Sem PDF conforme despacho.Current antibiotics effectiveness relies on higher doses and administration frequency, which are responsible for the growth of antimicrobial resistance (AMR). AMR is one of the major threatening issues of the century with last-line antibiotics already failing. To overcome such problems associated with bacterial infections, nanoparticles combined with antibiotics emerged as a promising strategy. In this work, nanocarriers comprising of gold–silica core–shell mesoporous nanoparticles (Au@MNs) and silica mesoporous nanoparticles (MNs) were synthesized, loaded with amoxicillin (Amox) and ofloxacin and investigated regarding its antibacterial activity towards S. aureus, methicillin-resistant S. aureus (MRSA), E. coli and P. aeruginosa. Both nanocarriers showed a beneficial role in the effective delivery of amoxicillin against MRSA and the well-known β-lactam resistant P. aeruginosa. Reductions of 10-fold (Amox@MNs) and 20-fold (Amox@Au@MNs) in the amount of antibiotic to treat P. aeruginosa; and a reduction of 20-fold (Amox@MNs) towards MRSA allied to a full reversion of resistance, strongly supports the promising potential of these nanocarriers to tackle antibiotics resistance.publishersversionpublishe
Contact sensitizer nickel sulfate activates the transcription factors NF-kB and AP-1 and increases the expression of nitric oxide synthase in a skin dendritic cell line
Nuclear factor kappa B (NF-kB) and activating protein-1 (AP-1) transcription factors are ubiquitously expressed signaling molecules known to regulate the transcription of a large number of genes involved in immune responses, namely the inducible isoform of nitric oxide synthase (iNOS). In this study, we demonstrate that a fetal skin-derived dendritic cell line (FSDC) produces nitric oxide (NO) in response to the contact sensitizer nickel sulfate (NiSO(4)) and increases the expression of the iNOS protein, as determined by immunofluorescence and Western blot analysis. The sensitizer NiSO(4) increased cytoplasmic iNOS expression by 31.9 +/- 10.3% and nitrite production, as assayed by the Griess reaction, by 27.6 +/- 9.5%. Electrophoretic mobility shift assay (EMSA), showed that 30 min of FSDC exposure to NiSO(4) activates the transcription factor NF-kB by 58.2 +/- 7.0% and 2 h of FSDC exposure to NiSO(4) activates the transcription factor AP-1 by 26.0 +/- 1.4%. Together, these results indicate that NiSO(4) activates the NF-kB and AP-1 pathways and induces iNOS expression in skin dendritic cells
Differential activation of nuclear factor kappa B subunits in a skin dendritic cell line in response to the strong sensitizer 2,4-dinitrofluorobenzene
Dendritic cell (DC) maturation is essential for the initiation of T-dependent immune responses. Nuclear factor kappa B (NF-kappaB) transcription factors are ubiquitously expressed signalling molecules, known to regulate the transcription of a large number of genes involved in immune responses, including cytokines and cell surface molecules. In this work, we studied the time-dependent activation of five members of the NF-kappaB family, p50, p52, p65, RelB and cRel, in a mouse skin DC line in response to stimulation with the strong sensitizer, 2,4-dinitrofluorobenzene (DNFB). Western blot assay revealed that exposure of fetal skin DC (FSDC) to DNFB induced the degradation of the inhibitor of NF-kappaB (IkappaB). Three out of its five members, i.e. p50, p52, and RelB, were similarly activated upon DNFB stimulation, with subsequent translocation of these subunits from the cytosol to the nucleus, but with different kinetics. In contrast, p65 expression was diminished in both the nucleus and the cytosol. The electrophoretic mobility shift assay (EMSA) showed that exposure of FSDC to DNFB induced DNA binding to NF-kappaB. Together, these results show that DNFB differentially activates the various members of the NF-kappaB family in skin DC
Granulocyte-macrophage colony-stimulating factor activates the transcription of nuclear factor kappa B and induces the expression of nitric oxide synthase in a skin dendritic cell line.
Nitric oxide (NO) produced by skin dendritic cells and keratinocytes plays an important role in skin physiology, growth and remodelling. Nitric oxide is also involved in skin inflammatory processes and in modulating antigen presentation (either enhancing or suppressing it). In this study, we found that GM-CSF stimulates the expression of the inducible isoform of nitric oxide synthase (iNOS) in a fetal-skin-derived dendritic cell line (FSDC) and, consequently, increases the nitrite production from 11.9 +/- 3.2 micromol/L (basal level) to 26.9 +/- 4.2 micromol/L. Pyrrolidinedithiocarbamate (PDTC) inhibits nitrite production, with a half maximal inhibitory concentration (IC50) of 19.3 micromol/L and the iNOS protein expression in FSDC. In addition, western blot assays revealed that exposure of FSDC to GM-CSF induces the phosphorylation and degradation of the inhibitor of NF-kappaB (IkB), with subsequent translocation of the p50, p52 and RelB subunits of the transcription nuclear factor kappa B (NF-kappaB) from the cytosol to the nucleus. Electrophoretic mobility shift assays (EMSA) showed that FSDC exposure to GM-CSF activates the transcription factor NF-kappaB. Together, these results show that GM-CSF induces iNOS expression in skin dendritic cells by a mechanism involving activation of the NF-kappaB pathway
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