Controlled synthesis of Pt-decorated Au nanostructure and its promoted activity toward formic acid electro-oxidation

Highly active Pt-decorated Au nanoparticles on carbon support with Pt:Au mole ratio ranging from 1:10 to 1:2 was successfully synthesized based on successive reduction strategy. The successful formation of this structure was suggested by transmission electron microscopy, UV-vis and voltammetry analyses. The electrocatalytic activity of this decorated structure toward formic acid oxidation surprisingly increases despite the low amount of Pt being used. At 0.1 V, the specific activity of PtAu/C with Pt/Au mole ratio 1:8 was more than one order of magnitude higher than the conventional Pt/C. The enhancement was attributed to the less Pt ensemble sites that the decorated structure possesses (ensemble effect) and the increase in the Pt atom reactivity on Au nanocrystal. The formic acid oxidation mechanism on this decorated structure was also elucidated using electrochemical impedance spectroscopy technique. It is proposed that besides the dehydrogenation reaction pathway happening on clean Pt sites, the reactive intermediate i.e. formate species could also be oxidized by the adsorbed water species on Pt at higher potential.     

Health biomarkers in a rat model after intake of organically grown carrots

BACKGROUND: Organic food is perceived as being of better quality and healthier than conventional foods although the scientific research on organic foodstuffs is highly contradictory. The aim of the present study was to investigate if intake of carrots from four different cultivation systems grown in two consecutive years would influence various biomarkers of health in a rat model. All rats were fed a diet with 40% carrot content. The carrots were grown under conventional (C), ‘minimalistic’ organic (O1), organic (O2), or ‘very’ organic cultivation systems (O3). A control group (CO) being fed standard rat chow was included. RESULTS: The plasma α‐tocopherol concentration was higher in the O2 carrot‐based diet group than in the C carrot based‐diet group in one year, while all other health biomarkers or nutrient content differences were observed between the CO diet and the carrot‐based diets. CONCLUSION: This well‐controlled field study demonstrated no clear influence of cultivation methods or harvest year on the nutritional quality of carrots or effect of cultivation methods on health‐related biomarkers in a sensitive rat model. However, the experimental set‐up and selected biomarkers could be used as a framework for further studies of health in relation to organic foodstuff. Copyright © 2012 Society of Chemical Industry     

A comparative study of the effect of gold seed particle preparation method on nanowire growth

Highly controlled particle-assisted growth of semiconductor nanowires has been performed for many years, and a number of novel nanowire-based devices have been demonstrated. Full control of the epitaxial growth is required to optimize the performance of devices, and gold seed particles are known to provide the most controlled growth. Successful nanowire growth from gold particles generated and deposited by various different methods has been reported, but no investigation has yet been performed to compare the effects of gold particle generation and deposition methods on nanowire growth. In this article we present a direct comparative study of the effect of the gold particle creation and deposition methods on nanowire growth characteristics and nanowire crystal structure, and investigate the limitations of the different generation and deposition methods used.      

Transport and fate of Cryptosporidium parvum oocysts in intermittent sand filters.

The transport potential of Cryptosporidium parvum (C. parvum) through intermittent, unsaturated, sand filters used for water and wastewater treatment was investigated using a duplicated, 2³ factorial design experiment performed in bench-scale, sand columns. Sixteen columns (dia=15 cm, L=60 cm) were dosed eight times daily for up to 61 days with 65,000 C. parvum oocysts per liter at 15°C. The effects of water quality, media grain size, and hydraulic loading rates were examined. Effluent samples were tested for pH, turbidity, and oocyst content. C. parvum effluent concentrations were determined by staining oocysts on polycarbonate filters and enumerating using epifluorescent microscopy. At completion, the columns were dismantled and sand samples were taken at discrete depths within the columns. These samples were washed in a surfactant solution and the oocysts were enumerated using immunomagnetic separation techniques.

The fine-grained sand columns (d₅₀=0.31 mm) effectively removed oocysts under the variety of conditions examined with low concentrations of oocysts infrequently detected in the effluent. Coarse-grained media columns (d₅₀=1.40 mm) yielded larger numbers of oocysts which were commonly observed in the effluent regardless of operating conditions. Factorial design analysis indicated that grain size was the variable which most affected the oocyst effluent concentrations in these intermittent filters. Loading rate had a significant effect when coarse-grained media was used and lesser effect with fine-grained media while the effect of feed composition was inconclusive. No correlations between turbidity, pH, and effluent oocyst concentrations were found. Pore-size calculations indicated that adequate space for oocyst transport existed in the filters. It was therefore concluded that processes other than physical straining mechanisms are mainly responsible for the removal of C. parvum oocysts from aqueous fluids in intermittent sand filters used under the conditions studied in this research.     

Controlled and automatic processing during animal word list generation in schizophrenia.

Controlled and automatic aspects of semantic-associative functioning in schizophrenia were investigated by evaluating performance on animal word list generation (WLG). Responses from control (n?=?47) and patient (n?=?38) participants were subjected to multidimensional scaling (MDS), cluster analysis (CA), and indices on the basis of number of shared attributes (SA) between consecutive responses. Patient MDS results accounted for less variance and contained more error than control data. CA results yielded fewer and less clear animal-response subgroups among patients yet demonstrated intact associations among strongly related exemplars. The SA indices revealed better clustering and more effective switching among response clusters in controls than patients. Results suggest that animal WLG in schizophrenia is compromised both by aberrant automatic semantic-associative network activation and by controlled processes such as search, access, and selection. This pattern is consistent with prominent frontotemporal pathology evident in the disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling cake buildup under TMP-step filtration in a membrane bioreactor: cake compressibility is significant

Fouling is inevitable in membrane bioreactors (MBRs) due to the complex nature of activated sludge, which contains a broad variety of potential foulants. Filter cakes that build up from sludge particles are traditionally highly compressible due to both the deformation of the individual sludge particles and the rearrangement of these particles in the cake. However, this phenomenon has been little examined in studies of fouling mechanisms in MBR systems. This study examines the properties of the cake layer, modeling the cake buildup and specific cake resistance (α), including compressibility, in terms of pressure-dependent α.The changes in fouling resistance during transmembrane pressure (TMP)-step filtration in an MBR setup were simulated using an empirical pressure dependence of the specific cake resistance and a simple mass balance model. The total change in fouling resistance in each TMP step could be divided into an initial rapid change in specific cake resistance due to filter cake compression followed by simple cake buildup. By including cake compression in this simple model, the model fitted the data with high precision. We demonstrated that compressibility should be considered when describing cake fouling in MBRs.     

An experiment on the security of the Norwegian electronic voting protocol

Even when using a provably secure voting protocol, an election authority cannot argue convincingly that no attack that changed the election outcome has occurred, unless the voters are able to use the voting protocol correctly. We describe one statistical method that, if the assumptions underlying the protocol’s security proof hold, could provide convincing evidence that no attack occurred for the Norwegian Internet voting protocol (or other similar voting protocols). To determine the statistical power of this method, we need to estimate the rate at which voters detect possible attacks against the voting protocol. We designed and carried out an experiment to estimate this rate. We describe the experiment and results in full. Based on the results, we estimate upper and lower bounds for the detection rate. We also discuss some limitations of the practical experiment.     

Key factors for achieving project success in integration of automotive mechatronics

In this paper, we present a multiple case study on integration of automotive mechatronic components. Based on the findings, we identify that the root causes of problems in integration are largely related to decisions omitted in electronic strategy. We present and recommend use of checklists defining key factors to address in order to achieve successful integration projects in terms of cost and quality. Our recommendations are defined by checklists for critical decisions in areas: functionality, platform, integration, and stakeholder involvement. The recommendations are established based on practitioner experience and then validated in a multiple case study. Five cases of integration are studied for different heavy vehicles in one company, and the fulfillment of our recommendations is measured. Finally we define project success criteria and we compare the level of fulfillment with the project success in terms of time plan and resource consumption. The main contribution of this study is the validated recommendations, each including a set of checkpoints that defines recommendation fulfillment. We also present defining characteristics to identify a high-risk project. We provide a set of observable project properties and show how they affect project risk.