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Pristine palladium nanoparticles were decorated on graphene nanosheets for the development of a low-cost, nonenzymatic ethanol sensor. The nanocomposite was characterized by ultraviolet–visible absorbance spectroscopy, infrared spectroscopy, and field emission scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. Cyclic voltammetry and chronoamperometry were used to quantify ethanol in alkaline media. A graphene palladium nanocomposite-modified glassy carbon electrode provided a detection limit of 2 mM with a linear dynamic range of 2–210 mM for ethanol determination. The nanocomposite exhibited excellent stability for 100 cyclic voltammetry scans. Ethanol oxidation was performed across a range of temperatures, unlike enzymatic based sensors. Moreover, the catalytic material showed a low activation energy and low onset potentials for the oxidation of ethanol. Interference studies with congeners of ethanol in fermentation chambers showed good selectivity for the analyte. The enhanced catalytic activity for ethanol detection involves the combination of pristine palladium nanoparticles with the enhanced conductivity of graphene. [ABSTRACT FROM PUBLISHER]

Discotic mesogenic molecules viz., hexahexylthiotriphenylene (HHTT) and hexahexyloxytriphenylene were applied, for the first time, as iodine-free redox electrolyte in dye-sensitised solar cells (DSSCs). The cell shows open circuit voltage (Voc) of 0.95 V, short circuit current density (Jsc) of 0.534 mA/cm2, fill factor 88.24% and overall power conversion efficiency (η) 0.45% in a typical fluorine doped tin oxide/TiO2/N719/HHTT/Pt DSSC configuration. Scanning electron microscopy was used to study surface profile of electrolytes while electrochemical impedance spectroscopy was used to understand the electrochemical behaviour of electrolytes. The photovoltaic parameters were measured under standard conditions using Oriel solar simulator class AAA. These first results demonstrate the potential of the discotic molecules as charge transporter and mediator and show promise to be used in iodine-free DSSCs. [ABSTRACT FROM PUBLISHER]

The methods of dihedral Fourier analysis are introduced and applied to describe the data-analytic properties of rotators, gyrators, separable fractional Fourier, and shearing operators in phase-space. The methods are also applied to introduce the notion of dihedral field orbits in phase-space as experimental designs or protocols for the statistical study of optical information, and to describe and classify these operators according to their response to field (dihedral) rotations and reversals. [ABSTRACT FROM AUTHOR]

This study evaluates the screening efficiency of the Hardy-Rand-Rittler (HRR) 4th edition colour test. This test was also compared with results from the Ishihara test. Thirty-nine subjects with congenital red-green deficiency and 120 colour normal subjects participated in the study. The subjects were shown the Ishihara (concise version, 2001) and the HRR (4th edn) pseudoisochromatic plates. Each plate was viewed for 3 s. A Macbeth Easel lamp was used for illumination (70 foot-candle). The HRR test had 100% sensitivity and the specificity was 63%. The overall efficiency of the HRR test was less than that of the Ishihara. The results also indicated that plate seven of HRR (4th edn) has poor screening efficiency. Thus the HRR is good for identifying colour deficient subjects but a caveat is that it fails too many normals. [ABSTRACT FROM AUTHOR]

Changes in the demographics indicates that the population older than 65 is on the rise because of the aging of the ‘baby boom’ generation. This aging trend and driving related accident statistics reveal the need for procedures and tests that would assess the driving ability of older adults and predict whether they would be safe or unsafe drivers. Literature shows that an attention based test called the useful field of view (UFOV) was a significant predictor of accident rates compared to any other visual function tests. The present study evaluates a qualitative trend on using motion perception tasks as a potential visual perceptual correlates in screening elderly drivers who might have difficulty in driving. Data was collected from 15 older subjects with a mean age of 71. Motion perception tasks included—speed discrimination with radial and lamellar motion, time to collision using prediction motion and estimating direction of heading. A motion index score was calculated which was indicative of performance on all of the above-mentioned motion tasks. Scores on visual attention was assessed using UFOV. A driving habit questionnaire was also administered for a self report on the driving difficulties and accident rates. A qualitative trend based on frequency distributions show that thresholds on the motion perception tasks are successful in identifying subjects who reported to have had difficulty in certain aspects of driving and had accidents. Correlation between UFOV and motion index scores was not significant indicating that probably different aspects of visual information processing that are crucial to driving behaviour are being tapped by these two paradigms. UFOV and motion perception tasks together can be a better predictor for identifying at risk or safe drivers than just using either one of them. [ABSTRACT FROM AUTHOR]

A reference axis for proper centration of the corneal working zone in refractive surgical techniques is required. This is difficult to define due to the fact that the human eye is not an aligned optical system. This theoretical note critically reviews and discusses the two commonly used reference axes; line of sight and the coaxially sighted corneal reflex. Taking into consideration the Stiles-Crawford effect, it is concluded that the coaxially sighted corneal reflex is remarkably close to the visual axis (or nodal axis) and is the preferred reference axis. [ABSTRACT FROM AUTHOR]

Several mixtures of hexanethiolate capped gold nanoparticles and discotic liquid crystals were prepared. The thermophysical properties of these mixtures were investigated using polarizing optical microscopy, differential scanning calorimetry and DC conductivity. Formation of columnar mesophase and about 250 times enhancement in the DC conductivity indicate inclusion of gold nanoparticles into the matrix of triphenylene based discotic liquid crystals. [ABSTRACT FROM AUTHOR]