The effect of potassium on the adsorption of gold on the TiO(2)(110)-1 × 1 surface

Density functional theory (DFT) total-energy calculations have been used to investigate the effect of potassium on the adsorption geometry of gold on a TiO(2)(110)- 1 × 1 surface. The gold prefers to sit between the two bridge oxygen atoms above the sixfold titanium atom. The addition of potassium significantly affects the bonding geometry of the gold. Potassium displaces gold from the bridge site and causes its migration to the top of the fivefold titanium atom. Our calculations suggest that potassium is bonded to the bridging oxygen atoms, and to the sixfold titanium atom as well as to gold. This excludes the formation of a K(2)O-like compound at the surface.     

The effect of ethanol on carbon-catalysed decomposition of methane

Because of its ecological character, the reaction of catalytic decomposition of methane (CDM) is expected to be an important future method of hydrogen generation. However, the main drawback of this technology is a relatively fast deactivation of the catalyst used, as a consequence of its pores blocking by the low-active methane-originated carbon deposit. This paper reports on an attempt of restricting the catalyst deactivation by introducing into the reaction system ethyl alcohol capable of forming in situ a potentially active in this reaction carbonaceous deposit. The catalyst used was activated carbon obtained from the waste material (hazelnut shells). The reactions of methane and ethanol decomposition were performed by the alternate method (for certain time methane was introduced into the reactor, and then it was replaced by ethanol). Three temperatures of the reactions were applied (750, 850 or 950 °C) and another variable was the duration of the ethanol decomposition. As follows from the results, an addition of ethanol has diverse effect on the catalytic activity of activated carbon and the amount of hydrogen formed depends on the temperatures of methane and ethanol decompositions and on the time of the reagent dosing.     

Evaluating and comparing three community small-scale wind electrification projects

Electrification systems based on renewable energy have proven suitable for providing electricity autonomously to rural communities. Among the technical options available, wind systems are increasingly getting attention. In the northern mountains of Peru, at 3800 m.a.s.l., three community wind electrification projects have been implemented. The technical solutions used in each project are different: wind vs. hybrid photovoltaic-wind systems; individual equipment vs. microgrids. This study aims to describe, evaluate and compare these three small-scale community wind electrification projects. The evaluation of the three projects was carried out by comparing previous and present scenario; attention has been focused on project design and technical aspects, socio-economic impacts and sustainability and management model. These three examples shed light on both the advantages and disadvantages of different technological options as well as on appropriate community-level management models.     

Investigating driving behaviour of older drivers with mild cognitive impairment using a portable driving simulator

While there is a large body of research indicating that individuals with moderate to severe dementia are unfit to drive, relatively little is known about the driving performance of older drivers with mild cognitive impairment (MCI). The aim of the current study was to examine the driving performance of older drivers with MCI on approach to intersections, and to investigate how their healthy counterparts perform on the same driving tasks using a portable driving simulator. Fourteen drivers with MCI and 14 age-matched healthy older drivers (aged 65–87 years) completed a 10-min simulator drive in an urban environment. The simulator drive consisted of stop-sign controlled and signal-controlled intersections. Drivers were required to stop at the stop-sign controlled intersections and to decide whether or not to proceed through a critical light change at the signal-controlled intersections. The specific performance measures included; approach speed, number of brake applications on approach to the intersection (either excessive or minimal), failure to comply with stop signs, and slower braking response times on approach to a critical light change. MCI patients in our sample performed more poorly than controls across a number of variables. However, because the trends failed to reach statistical significance it will be important to replicate the study using a larger sample to qualify whether the results can be generalised to the broader population.     

Aptamer-based viability impedimetric sensor for viruses

The development of aptamer-based viability impedimetric sensor for viruses (AptaVISens-V) is presented. Highly specific DNA aptamers to intact vaccinia virus were selected using cell-SELEX technique and integrated into impedimetric sensors via self-assembly onto a gold microelectrode. Remarkably, this aptasensor is highly selective and can successfully detect viable vaccinia virus particles (down to 60 virions in a microliter) and distinguish them from nonviable viruses in a label-free electrochemical assay format. It also opens a new venue for the development of a variety of viability sensors for detection of many microorganisms and spores.     

Nanoassisted Laser Desorption-Ionization-MS Imaging of Tumors

The ability of nanoassisted laser desorption-ionization mass spectrometry (NALDI-MS) imaging to provide selective chemical monitoring with proper spatial distribution of lipid profiles from tumor tissues after plate imprinting has been tested. NALDI-MS imaging identified and mapped several potential lipid biomarkers in a murine model of melanoma tumor (inoculation of B16/F10 cells). It also confirmed that the in vivo treatment of tumor bearing mice with synthetic supplement containing phosphoethanolamine (PHO-S) promoted an accentuated decrease in relative abundance of the tumor biomarkers. NALDI-MS imaging is a matrix-free LDI protocol based on the selective imprinting of lipids in the NALDI plate followed by the removal of the tissue. It therefore provides good quality and selective chemical images with preservation of spatial distribution and less interference from tissue material. The test case described herein illustrates the potential of chemically selective NALDI-MS imaging for biomarker discovery.     

Application of matrix-assisted laser desorption/ionization mass spectrometric imaging for photolithographic structuring

The aim of this contribution is the application of matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) in the area of photolithographic structuring. As proof of concept, this method was used to image an UV exposed negative photoresist layer, which is generally used to manufacture printed circuit boards (PCB) for electronic components. The negative photoresist layer consisting of the main component novolac, benzophenone as the active component, and the solvent tetrahydrofuran was mixed with the matrix dithranol and the salt additive LiTFA and spin-coated onto an ITO-conductive glass slide. To imprint an image on the created surface, a transparency with a printed wiring diagram was placed on top of it and irradiated by UV light for 15 min. The inspection of the efficient imprinting of the microstructure onto the photoresist layer was performed by MALDI-MSI. This unique application represents a further step toward the surface analysis of polymer films by this emerging life science imaging technique.     

Electrothermal supercharging of proteins in native electrospray ionization

The formation of high charge-state protein ions with nanoelectrospray ionization (nESI) from purely aqueous ammonium bicarbonate solutions at neutral pH, where the proteins have native or native-like conformations prior to ESI droplet formation, is demonstrated. This "electrothermal" supercharging method depends on the temperature of the instrument entrance capillary, the nESI spray potential, and the solution ionic strength and buffer, although other factors almost certainly contribute. Mass spectra obtained with electrothermal supercharging appear similar to those obtained from denaturing solutions where charging beyond the total number of basic sites can be achieved. For example, a 17+ ion of bovine ubiquitin was formed by nESI of a 100 mM ammonium bicarbonate, pH 7.0, solution, which is three more charges than the total number of basic amino acids plus the N-terminus. Heating of the ESI droplets in the vacuum/atmosphere interface and the concomitant denaturation of the protein in the ESI droplets prior to ion formation appears to be the primary origin of the very high charge-state ions formed from these purely aqueous, buffered solutions. nESI mass spectra resembling those obtained under traditional native or denaturing conditions can be reversibly obtained simply by toggling the spray voltage between low and high values.     

Fully tunable active polarization imager for contrast enhancement and partial polarimetry

We present the design and the practical implementation of a polarimetric imaging system based on liquid-crystal modulators that allows generation and analysis of any polarization state on the Poincaré sphere. This system is more versatile than standard Mueller imagers that are based on optimized, but limited, sets of illumination and analysis states. Examples of benefits brought by these extra degrees of freedom are illustrated on two different applications: contrast enhancement and extraction of partial polarimetric properties of a scene.     

On the influence of noise statistics on polarimetric contrast optimization

In active scalar polarimetric imaging systems, the illumination and analysis polarization states are degrees of freedom that can be used to maximize the performance. These optimal states depend on the statistics of the noise that perturbs image acquisition. We investigate the problem of optimization of discrimination ability (contrast) of such imagers in the presence of three different types of noise statistics frequently encountered in optical images (Gaussian, Poisson, and Gamma). To compare these different situations within a common theoretical framework, we use the Bhattacharyya distance and the Fisher ratio as measures of contrast. We show that the optimal states depend on a trade-off between the target/background intensity difference and the average intensity in the acquired image, and that this trade-off depends on the noise statistics. On a few examples, we show that the gain in contrast obtained by implementing the states adapted to the noise statistics actually present in the image can be significant.