In vitro resistance of Burkholderia cepacia complex isolates to reactive oxygen species in relation to catalase and superoxide dismutase production

The Burkholderia cepacia complex comprises groups of genomovars (genotypically distinct strains with very similar phenotypes) that have emerged as important opportunistic pathogens in cystic fibrosis (CF) patients. The inflammatory response against bacteria in the airways of CF individuals is dominated by polymorphonuclear cells and involves the generation of oxidative stress, which leads to further inflammation and tissue damage. Bacterial catalase, catalase-peroxidase and superoxide dismutase activities may contribute to the survival of B. cepacia following exposure to reactive oxygen metabolites generated by host cells in response to infection. In the present study the authors investigated the production of catalase, peroxidase and SOD by isolates belonging to various genomovars of the B. cepacia complex. Production of both catalase and SOD was maximal during late stationary phase in almost all isolates examined. Native PAGE identified 13 catalase electrophoretotypes and two SOD electrophoretotypes (corresponding to an Fe-SOD class) in strains belonging to the six genomovars of the B. cepacia complex. Seven out of 11 strains displaying high-level survival after H(2)O(2) treatment in vitro had a bifunctional catalase/peroxidase, and included all the genomovar III strains examined. These isolates represent most of the epidemic isolates that are often associated with the cepacia syndrome. The majority of the isolates from all the genomovars were resistant to extracellular O(-)(2), while resistance to intracellularly generated O(-)(2)was highly variable and could not be correlated with the detected levels of SOD activity. Altogether the results suggest that resistance to toxic oxygen metabolites from extracellular sources may be a factor involved in the persistence of B. cepacia in the airways of CF individuals.

Age-related changes in non-receptor dependent generation of reactive oxygen species from phagocytes of healthy adults

Several authors have shown that neutrophil generation of reactive oxygen species (ROS) declines with advancing age. Similar changes have also been suggested in monocytes. In both cases alterations in second messenger activity have been implicated as the most likely explanation for these observations. The aim of this study was to investigate the effect of age on phagocyte ROS generation, stimulated by the direct activation of protein kinase C (PKC). Venous blood was drawn from normal healthy subjects, cells were separated on a double density gradient into mononuclear and polymorphonuclear (pmn) cells. Phorbol myristate acetate (PMA) was employed as a cell stimulus. Superoxide generation was measured by cytochrome c reduction and myeloperoxidase (MPO) products by measurement of peak luminol chemiluminescence (CL). Fifty-eight subjects, 25 males and 33 females, were studied, median age 49 years (range 26-88 years). Polymorphonuclear cell superoxide generation was significantly higher in males and there was a trend towards higher pmn MPO product generation in males. Using Spearman's ranked correlation coefficient, monocyte superoxide generation was negatively correlated with age (r = -0.473, P <0.001). No changes in the generation of MPO products was found. There were also trends towards a negative correlation of pmn cytochrome c reduction and peak luminol CL with age in males but not females. Since PMA directly activates protein kinase C, reduced monocyte superoxide generation with increasing age appears to be related to alterations in the ROS generating system downstream of the cell receptor. Impaired monocyte superoxide generation may have implications for non-specific defence against certain infections and early tumour growth in the elderly. Factors underlying these changes in monocyte function therefore require further study.

Infection systems biology:from reactive to proactive (P4) medicine

This short review establishes the conceptual bases and discusses the principal aspects of P4-shorthand for predictive, preventive, personalized and participatory medicine-medicine, in the framework of infectious diseases. P4 medicine is a new way to approach medical care; instead of acting when the patient is sick, physicians will be able to detect early warnings of disease to take early action. Furthermore, people might even be able to adjust their lifestyles to prevent disease. P4 medicine is fuelled by systems approaches to disease, including methods for personalized genome sequencing and new computational techniques for building dynamic disease predictive networks from massive amounts of data from a variety of OMICs. An excellent example of the effectiveness of the P4 medicine approach is the change in cancer treatments. Emphasis is placed on early detection, followed by genotyping of the patient to use the most adequate treatment according to the genetic background. Cardiovascular diseases and perhaps even neurodegenerative disorders will be the next targets for P4 medicine. The application of P4 medicine to infectious diseases is still in its infancy, but is a promising field that will provide much benefit to both the patients and the health-care system.

Reactive dye adsorption onto a novel mesoporous carbon

A new mesoporous carbon (MCSG60) was developed using an inexpensive commercial mesoporous silica gel as a template and sucrose as the carbon source. The surface area, porosity and density of the carbon were determined. The material possesses a high specific surface area and pore volume accessible for most typical aqueous pollutants. The adsorbent material was tested in a batch dye adsorption system. The behaviour of three reactive dyes adsorbed onto MCSG60 was evaluated (Naphthol Blue Black, NBB; Reactive Black 5, RB5; and Remazol Brilliant Blue R, RBBR). The maximum adsorption capacities obtained for the dyes were: 270. mg/g for NBB; 270. mg/g for RB5; and 280. mg/g for RBBR. Kinetic studies indicated that the adsorption process onto the mesoporous carbon was rapid and that equilibrium was reached in less than 1. h for all the dye systems investigated. Further batch experiments showed MCSG60 successfully adsorbed the dyes over a wide pH range and at low adsorbate concentration. The adsorption potential of MCSG60 for dye removal was further evaluated using a fixed-bed adsorption column. © 2013 Elsevier B.V.

Removal of natural hormones in dairy farm wastewater using reactive and sorptive materials

The objective of this study was to examine the estrogen and androgen hormone removal efficiency of reactive (Connelly zero-valent iron (ZVI), Gotthart Maier ZVI) and sorptive (AquaSorb 101 granular activated carbon (GAC) and OrganoLoc PM-100 organo clay (OC)) materials from HPLC grade water and constructed wetland system (CWS) treated dairy farm wastewater. Batch test studies were performed and hormone concentration analysis carried out using highly sensitive reporter gene assays (RGAs). The results showed that hormonal interaction with these materials is selective for individual classes of hormones. Connelly ZVI and AquaSorb 101 GAC were more efficient in removing testosterone (Te) than 17?-estradiol (E2) and showed faster removal rates of estrogen and androgen than the other materials. Gotthart Maier ZVI was more efficient in removing E2 than Te. OrganoLoc PM-100 OC achieved the lowest final concentration of E2 equivalent (EEQ) and provided maximum removal of both estrogens and androgens.

Electronic, structural, and reactive properties of ultrathin aluminum oxide films on Pt(111)

Low-energy electron diffraction, X-ray photoelectron spectroscopy, high-resolution electron energy-loss spectroscopy, scanning tunneling microscopy, and temperature-programmed reaction spectrometry results are reported for the structural and reactive behavior of alumina films grown on Pt(111) as a function of thickness and oxidation temperature. Submonolayer Al films undergo compete oxidation at 300 K, annealing at 1100 K resulting in formation of somewhat distorted crystalline gamma-alumina, Thicker deposits require 800 K oxidation to produce Al2O3, and these too undergo crystallization at 800 K, yielding islands of apparently undistorted gamma-alumina on the Pt(111) surface. Oxidation of a p(2 x 2) Pt3Al surface alloy occurs only at>800 K, resulting in Al extraction, These alumina films on Pt(lll) markedly increase the coverage of adsorbed SO4 resulting from SO2 chemisorption onto oxygen-precovered surfaces. This results in enhanced propane uptake and subsequent reactivity relative to SO4/Pt(111). A bifunctional mechanism is proposed to account for our observations, and the relevance of these to an understanding of the corresponding dispersed systems is discussed.

Cross-sectional associations of C-reactive protein with vascular risk factors and vascular complications in the DCCT/EDIC cohort

To determine the relationships between C-reactive protein (CRP) levels and features of Type 1 diabetes.

Multi-Objective Reactive Power Support from Wind farms for Network Performance Enhancement

This paper examines the ability of the doubly fed induction generator (DFIG) to deliver multiple reactive power objectives during variable wind conditions. The reactive power requirement is decomposed based on various control objectives (e.g. power factor control, voltage control, loss minimisation, and flicker mitigation) defined around different time frames (i.e. seconds, minutes, and hourly), and the control reference is generated by aggregating the individual reactive power requirement for each control strategy. A novel coordinated controller is implemented for the rotor-side converter and the grid-side converter considering their capability curves and illustrating that it can effectively utilise the aggregated DFIG reactive power capability for system performance enhancement. The performance of the multi-objective strategy is examined for a range of wind and network conditions, and it is shown that for the majority of the scenarios, more than 92% of the main control objective can be achieved while introducing the integrated flicker control scheme with the main reactive power control scheme. Therefore, optimal control coordination across the different control strategies can maximise the availability of ancillary services from DFIG-based wind farms without additional dynamic reactive power devices being installed in power networks.

Capability Curve Based Enhanced Reactive Power Control Strategy for Stability Enhancement and Network Voltage Management

Reactive power has become a vital resource in modern electricity networks due to increased penetration of distributed generation. This paper examines the extended reactive power capability of DFIGs to improve network stability and capability to manage network voltage profile during transient faults and dynamic operating conditions. A coordinated reactive power controller is designed by considering the reactive power capabilities of the rotor-side converter (RSC) and the grid-side converter (GSC) of the DFIG in order to maximise the reactive power support from DFIGs. The study has illustrated that, a significant reactive power contribution can be obtained from partially loaded DFIG wind farms for stability enhancement by using the proposed capability curve based reactive power controller; hence DFIG wind farms can function as vital dynamic reactive power resources for power utilities without commissioning additional dynamic reactive power devices. Several network adaptive droop control schemes are also proposed for network voltage management and their performance has been investigated during variable wind conditions. Furthermore, the influence of reactive power capability on network adaptive droop control strategies has been investigated and it has also been shown that enhanced reactive power capability of DFIGs can substantially improve the voltage control performance.

Demonstration of antibodies in archival sera from Canadian seals reactive with a European isolate of phocine distemper virus

Sera from seals infected during the 1988 European epizootic of phocine distemper virus and sera from Canadian seals collected since 1972 have been tested for the presence of antibodies to morbillivirus. Approximately one third of the Canadian sera have been shown to contain anti-morbillivirus antibodies; the possibility that these populations of seals provided a source of infection for European seals is discussed.

Chemical kinetics and reactive species in atmospheric pressure helium-oxygen plasmas with humid-air impurities

In most applications helium-based plasma jets operate in an open-air environment. The presence of humid air in the plasma jet will influence the plasma chemistry and can lead to the production of a broader range of reactive species. We explore the influence of humid air on the reactive species in radio frequency (rf)-driven atmospheric-pressure helium-oxygen mixture plasmas (He-O, helium with 5000 ppm admixture of oxygen) for wide air impurity levels of 0-500 ppm with relative humidities of from 0% to 100% using a zero-dimensional, time-dependent global model. Comparisons are made with experimental measurements in an rf-driven micro-scale atmospheric pressure plasma jet and with one-dimensional semi-kinetic simulations of the same plasma jet. These suggest that the plausible air impurity level is not more than hundreds of ppm in such systems. The evolution of species concentration is described for reactive oxygen species, metastable species, radical species and positively and negatively charged ions (and their clusters). Effects of the air impurity containing water humidity on electronegativity and overall plasma reactivity are clarified with particular emphasis on reactive oxygen species. © 2013 IOP Publishing Ltd.