Robust multi‐model control of an autonomous wind power system

This article presents a robust multi‐model control structure for a wind power system that uses a variable speed wind turbine (VSWT) driving a permanent magnet synchronous generator (PMSG) connected to a local grid. The control problem consists in maximizing the energy captured from the wind for varying wind speeds. The VSWT‐PMSG linearized model analysis reveals the resonant nature of its dynamic at points on the optimal regimes characteristic (ORC). The natural frequency of the system and the damping factor are strongly dependent on the operating point on the ORC. Under these circumstances a robust multi‐model control structure is designed. The simulation results prove the viability of the proposed control structure. Copyright © 2006 John Wiley & Sons, Ltd.     

Aberration corrected scanning transmission electron microscopy and electron energy loss spectroscopy studies of epitaxial Fe/MgO/(001)Ge heterostructures

Aberration correction in the scanning transmission electron microscope combined with electron energy loss spectroscopy allows simultaneous mapping of the structure, the chemistry and even the electronic properties of materials in one single experiment with spatial resolutions of the order of one Ångström. Here the authors will apply these techniques to the characterization of epitaxial Fe/MgO/(001)Ge and interfaces with possible applications for tunneling junctions, and the authors will show that epitaxial MgO films can be grown on a (001)Ge substrates by molecular beam epitaxy and how it is possible to map the chemistry of interfaces with atomic resolution.     

Photoactivity of brookite–rutile TiO2 nanocrystalline mixtures obtained by heat treatment of hydrothermally prepared brookite

Pure brookite phase was prepared by hydrothermal synthesis of titanium peroxo-complex in the presence of glycolic acid at 220 °C. The structure of prepared brookite samples was determined by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED). The prepared brookite was studied by in situ high temperature XRD in air. The morphology and microstructure characteristics were also obtained by transmission electron microscopy (TEM). The nitrogen adsorption–desorption was used for determination of surface area (BET) and porosity. The method of UV–vis diffuse reflectance spectroscopy was employed to estimate band-gap energies of prepared brookite. The photocatalytic activity of the prepared titania samples were assessed by photocatalytic decomposition of Orange II dye in an aqueous slurry under UV irradiation at 365 nm wavelength. The photocatalytic activity of the prepared sample brookite heated to 800 °C in air was higher than nanocrystalline unheated brookite powder.     

Ag nanoparticles capped by a nontoxic polymer: Electrochemical and spectroscopic characterization of a novel nanomaterial for glucose detection

Modified electrodes with metal or metal oxides nanoparticles are particularly appealing to improve sensor performances and fabricate miniaturized devices, as required also in glucose detection. A Pt electrode modified by drop casting of a novel nanostructured film based on silver nanoparticles (Ag-NPs) capped in a commercial nontoxic polyvinyl alcohol (PVA) matrix is proposed here as a valid alternative to classical glucose (bio)sensors. The extensive electrochemical and spectroscopic characterization by X-ray Photoelectron Spectroscopy (XPS) of this advanced nanomaterial is presented to study its response to glucose and to investigate the chemical nature of deposited Ag.     

Proteome Analysis of Thyroid Cancer Cells After Long-Term Exposure to a Random Positioning Machine

Annulling gravity during cell culturing triggers various types of cells to change their protein expression in a time dependent manner. We therefore decided to determine gravity sensitive proteins and their period of sensitivity to the effects of gravity. In this study, thyroid cancer cells of the ML-1 cell line were cultured under normal gravity (1?g) or in a random positioning machine (RPM), which simulated near weightlessness for 7 and 11?days. Cells were then sonicated and proteins released into the supernatant were separated from those that remained attached to the cell fragments. Subsequently, both types of proteins were fractionated by free-flow isoelectric focussing (FF-IEF). The fractions obtained were further separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to which comparable FF-IEF fractions derived from cells cultured either under 1?g or on the RPM had been applied side by side. The separation resulted in pairs of lanes, on which a number of identical bands were observed. Selected gel pieces were excised and their proteins determined by mass spectrometry. Equal proteins from cells cultured under normal gravity and the RPM, respectively, were detected in comparable gel pieces. However, many of these proteins had received different Mascot scores. Quantifying heat shock cognate 71?kDa protein, glutathione S-transferase P, nucleoside diphosphate kinase A and annexin-2 by Western blotting using whole cell lysates indicated usefulness of Mascot scores for selecting the most efficient antibodies.     

Factors associated with alcohol and drug use among traffic crash victims in southern Brazil

Objective

To investigate the prevalence of and factors associated with alcohol- or drug-related traffic crashes (TC) in a sample of TC victims who were admitted to the two emergency rooms of Porto Alegre in southern Brazil.

Methods

A cross-sectional study with consecutive samples was used. Victims of non-fatal TCs (as drivers, passengers or pedestrians) who had presented at emergency rooms during the 45 days of data collection were selected. Subjects participated in a structured interview, were breathalyzed and underwent salivary drug testing. A multinomial logistic regression model was used to verify factors associated with alcohol or drug use.

Results

Of the 609 victims who participated in the interview, 72% were male, and the median age was 29 years (interquartile range 23.0–40.0 years). The drivers were mostly men (p < 0.001), with a higher binge drinking rate (p = 0.003) and marijuana use (p = 0.005) than seen in pedestrian and passengers. The prevalence of a positive blood alcohol concentration (BAC) ranged from 7.8% among the drivers to 9.2% among the pedestrians (p = 0.861), and the cannabis prevalence was 13.3% among the drivers. The variables associated with an alcohol-related accident were binge drinking in the prior 12 months (OR 2.4; CI 95% 1.1–5.1) and coming from a party/bar (OR 8.7; CI 95% 2.8–26.7). Alcohol abuse or dependence increased by 5.2-fold the chance of another substance-related TC.

Conclusion

The large number of individuals found in TC-related emergency room visits in a short time frame is evidence of the Brazilian epidemic of TC. The data showed that alcohol abuse or dependence also increases the risk of intoxication by other drugs, and they point to alcohol and drug use as a major problem requiring specific TC-related public policies and law enforcement.     

Efficient, global-scale quantification of absolute protein amounts by integration of targeted mass spectrometry and two-dimensional gel-based proteomics

Knowledge on absolute protein concentrations is mandatory for the simulation of biological processes in the context of systems biology. A novel approach for the absolute quantification of proteins at a global scale has been developed and its applicability demonstrated using glucose starvation of the Gram-positive model bacterium Bacillus subtilis and the pathogen Staphylococcus aureus as proof-of-principle examples. Absolute intracellular protein concentrations were initially determined for a preselected set of anchor proteins by employing a targeted mass spectrometric method and isotopically labeled internal standard peptides. Known concentrations of these anchor proteins were then used to calibrate two-dimensional (2-D) gels allowing the calculation of absolute abundance of all detectable proteins on the 2-D gels. Using this approach, concentrations of the majority of metabolic enzymes were determined, and thus a quantification of the players of metabolism was achieved. This new strategy is fast, cost-effective, applicable to any cell type, and thus of value for a broad community of laboratories with experience in 2-D gel-based proteomics and interest in quantitative approaches. Particularly, this approach could also be utilized to quantify existing data sets with the aid of a few standard anchor proteins.     

ECRH for JET: A feasibility study

For JET to fulfil its mission in preparing ITER operation, the installation of an electron cyclotron resonance heating system on JET would be desirable. The study described in this paper has investigated the feasibility of installing such a system on JET. The principal goals of such a system are: current drive over a range of radii for NTM stabilization, sawtooth control and current profile tailoring and central electron heating to equilibrate electron and ion temperatures in high performance discharges. The study concluded that a 12 gyrotron, 10 MW, system at the ITER frequency (170 GHz) adapted for fields of 2.7–3.3 T would be appropriate for the operation planned in JET. An antenna allowing toroidal and poloidal steering over a wide range is being designed, using the ITER upper launcher steering mechanism. The use of ITER diamond windows and transmission line technology is suggested while power supply solutions partially reusing existing JET power supplies are proposed. Detailed planning shows that such a system can be operational in about 5 years from the time that the decision to proceed is taken. The cost and required manpower associated with implementing such a system on JET has also been estimated.     

Combinations of Histone Deacetylase Inhibitors with Distinct Latency Reversing Agents Variably Affect HIV Reactivation and Susceptibility to NK Cell-Mediated Killing of T Cells That Exit Viral Latency

The ‘shock-and-kill’ strategy to purge the latent HIV reservoir relies on latency-reversing agents (LRAs) to reactivate the provirus and subsequent immune-mediated killing of HIV-expressing cells. Yet, clinical trials employing histone deacetylase inhibitors (HDACis; Vorinostat, Romidepsin, Panobinostat) as LRAs failed to reduce the HIV reservoir size, stressing the need for more effective latency reversal strategies, such as 2-LRA combinations, and enhancement of the immune responses. Interestingly, several LRAs are employed to treat cancer because they up-modulate ligands for the NKG2D NK-cell activating receptor on tumor cells. Therefore, using in vitro T cell models of HIV latency and NK cells, we investigated the capacity of HDACis, either alone or combined with a distinct LRA, to potentiate the NKG2D/NKG2D ligands axis. While Bortezomib proteasome inhibitor was toxic for both T and NK cells, the GS-9620 TLR-7 agonist antagonized HIV reactivation and NKG2D ligand expression by HDACis. Conversely, co-administration of the Prostratin PKC agonist attenuated HDACi toxicity and, when combined with Romidepsin, stimulated HIV reactivation and further up-modulated NKG2D ligands on HIV⁺ T cells and NKG2D on NK cells, ultimately boosting NKG2D-mediated viral suppression by NK cells. These findings disclose limitations of LRA candidates and provide evidence that NK cell suppression of reactivated HIV may be modulated by specific 2-LRA combinations.     

Multivariate Optimisation and Validation of a Method for the Separation of Five Artificial Sweeteners by UPLC-DAD in Nine Food Matrices

Food Analytical Methods - A new, fast and efficient method was developed for the separation and simultaneous quantification of acesulfame-K, aspartame, cyclamate, neotame and saccharin in food by...