Bayesian recursive estimation of linear dynamic system states from measurement information

The evaluation of uncertainty in dynamic measurements has recently become a demanding issue. A Bayesian approach is employed here to derive the equations required to recursively generate the solution to the problem of estimating (and predicting) the states of linear dynamic systems. It is shown that this approach allows a derivation of Kalman’s filtering algorithm which is more easily accessible to those involved with dynamic measurements. The complete time-varying Kalman filter is particularly useful when the linear dynamic system and/or signal statistics are time varying and also when optimum estimates are required from the very beginning.     

Determination of deoxynivalenol in wheat-based breakfast cereals marketed in Portugal.

Deoxynivalenol (DON), also known as vomitoxin, is one of a group of closely related secondary fungal metabolites--the trichothecenes--and is produced predominantly by several species of the genus Fusarium, especially Fusarium graminearum. The present study was carried out to evaluate the natural occurrence of DON in different kinds of wheat-based breakfast cereals widely consumed by the population. A total of 88 commercially available samples of wheat-based breakfast cereals were randomly collected from different supermarkets in Lisbon, Portugal. The samples were analyzed using immunoaffinity column, and DON was quantified by liquid chromatography. Detection limit was 100 microg/kg. Average recovery of DON was 80%. Of 88 analyzed samples, 72.8% contained levels of DON between 103 and 6,040 microg/kg, with mean level of 754 microg/kg, and 24 samples (27.2%) were not contaminated (< 100 microg/kg). These results indicate an incidence of this mycotoxin in these products, and the authors suggest a monitoring for the prevention of molds and mycotoxins. This is the first report in Portugal on natural contamination with DON in wheat-based breakfast cereals.     

NETmix®, a new type of static mixer: Modeling,simulation, macromixing,and micromixing characterization

NETmix® is a new technology for static mixing based on a network of chambers connected by channels. The NETmix® model is the basis of a flow simulator coupled with chemical reaction used to characterize macro and micromixing in structured porous media. The chambers are modeled as perfectly mixing zones and the channels as plug flow perfect segregation zones. A segregation parameter is introduced as the ratio between the channels volume and the whole network volume. Different kinetics and reactants injection schemes can be implemented. Results show that the number of rows in the flow direction and the segregation parameter control both macro and micromixing, but the degree of micromixing is also controlled by the reactants injection scheme. The NETmix® model enables the systematic study of micromixing and macromixing for different network structures and reaction schemes, enabling the design of network structures to ensure the desired yield and selectivity. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Luminescent Conjugated Oligothiophenes for Sensitive Fluorescent Assignment of Protein Inclusion Bodies

Small hydrophobic ligands identifying intracellular protein deposits are of great interest, as protein inclusion bodies are the pathological hallmark of several degenerative diseases. Here we report that fluorescent amyloid ligands, termed luminescent conjugated oligothiophenes (LCOs), rapidly and with high sensitivity detect protein inclusion bodies in skeletal muscle tissue from patients with sporadic inclusion body myositis (s‐IBM). LCOs having a conjugated backbone of at least five thiophene units emitted strong fluorescence upon binding, and showed co‐localization with proteins reported to accumulate in s‐IBM protein inclusion bodies. Compared with conventional amyloid ligands, LCOs identified a larger fraction of immunopositive inclusion bodies. When the conjugated thiophene backbone was extended with terminal carboxyl groups, the LCO revealed striking spectral differences between distinct protein inclusion bodies. We conclude that 1) LCOs are sensitive, rapid and powerful tools for identifying protein inclusion bodies and 2) LCOs identify a wider range of protein inclusion bodies than conventional amyloid ligands.     

Crystallization of amorphous indium zinc oxide thin films produced by radio-frequency magnetron sputtering

In this work we studied indium zinc oxide (IZO) thin films deposited by r.f. magnetron sputtering at room temperature. The films were annealed at high temperature (1100 K) in vacuum, and the oxygen exodiffusion was monitored in-situ. The results showed three main peaks, one at approximately 600 K, other at approximately 850 K and the last one at 940 K, which are probably from oxygen bonded in the film surface and in the bulk, respectively. The initial amorphous structure becomes microcrystalline, according to the X-ray diffraction. The electrical conductivity of the films decreases (about 3 orders of magnitude), after the annealing treatment.This behavior could be explained by the crystallization of the structure, which affects the transport mechanism. Apart from the changes in the material structure, a small variation was observed on the absorption coefficient.     

X-ray spectra emitted by Cl ions in ECRIS plasmas

We study the contribution of the most important processes leading to the creation of excited states of Cl¹⁴⁺ ions from the ground configurations of Cl ions in an Electron Cyclotron Resonance Ion Source (ECRIS), which lead to the emission of K X-ray lines. Theoretical values for inner-shell excitation, K and KL ionization cross-sections, and energies and transition probabilities for the de-excitation processes are calculated in the framework of the Multi-Configuration Dirac-Fock (MCDF) method. With reasonable assumptions about the electron energy distribution, a theoretical Kα X-ray spectrum is obtained, which reproduces closely a recent experimental result.     

Effects of burning of biomass on satellite estimations of solar irradiation in Brazil

Atmospheric combustion products from forest fires in the Brazilian Amazon and ‘Cerrado’ regions during the dry season (July–October) induce systematic deviations on the routine satellite techniques for the assessment of solar energy resource information. This study, based on clear-sky days, has shown model overestimations of the incoming solar radiation as high as 44%. On the average, clear-sky model overestimation was four times larger than that found for clear-sky days in regions outside the biomass-burning season. A positive correlation between the combustion products of black carbon, total aerosols, CO, N₂O, CH₄, and the number of fire spots counted by the AVHRR sensor from the NOAA series satellites suggests a possible mechanism for the parameterization of these effects on the radiation transfer methods.     

Influence of Dekkera bruxellensis on the contents of anthocyanins,organic acids and volatile phenols of Dão red wine

The anthocyanin, organic acid and volatile phenol compositions of red wine obtained from Touriga Nacional grapes growing in the Dão region (Portugal) were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. By these means, nine anthocyanic compounds (malvidin-3,5-O-diglucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside, malvidin-3-O-glucoside, delphinidin, cyanidin, pelargonidin and malvidin), six organic acids (ketoglutaric, tartaric, malic, quinic, lactic and shikimic acids) and two volatile phenols (4-ethylguaiacol and 4-ethylphenol) were identified and quantified. Malvidin-3-O-glucoside, the pair lactic plus shikimic acids and 4-ethylguaiacol were the main anthocyanin, organic acids and volatile phenol, respectively. The effects of nine different Dekkera bruxellensis strains on these chemical parameters were also evaluated. The results obtained indicate that some strains of D. bruxellensis yeast are able to cause deterioration of red wine from the Dão region during its maturation by the production of volatile phenols, namely 4-ethylphenol.     

Immunoglobulin A antibodies to Helicobacter pylori

Serological testing for immunoglobulin G (IgG) antibodies to Helicobacter pylori has proven useful in supporting the diagnosis of infection with this organism, but the clinical value of IgA antibodies in H. pylori-related gastritis remains controversial. The purpose of our study was to determine the frequency of IgA-positive IgG-negative patients with symptoms of gastrointestinal (GI) disorders, thus assessing the clinical utility of IgA testing for H. pylori-related gastritis. It was found previously that the frequency of infected individuals in this category (IgA positive and IgG negative) is about 2%, but a large number of IgG-negative patients with GI disorders suggestive of H. pylori infection have not been investigated until now.