Selective reductions using visible light photocatalysts of supported gold nanoparticles

Photocatalytic synthesis using visible light is a desirable chemical process because of its potential to utilize sunlight. Supported gold nanoparticles (Au-NPs) were found to be efficient photocatalysts and the effects of the supports were identified including CeO2, TiO2, ZrO2, Al2O3, and zeolite Y. In particular Au/CeO2 exhibited the high catalytic activity to reduce nitroaromatics to azo compounds, hydrogenate azobenzene to hydroazobenzene, reduce ketones to alcohols, and deoxygenate epoxides to alkenes at ambient temperatures, under irradiation of visible light (or simulated sunlight). The reac-tive efficiency depends on two primary factors: one is the light adsorption of catalysts and another is the driving ability of catalysts corresponding to the reactants. The light absorption by Au-NPs is due to surface plasmon resonance effect or inter-band electron transition; this is related to the reduction ability of the photocatalysts. Irradiation with shorter wavelengths can excite the conduction electrons in Au-NPs to higher energy levels and as a result, induce reduction with more negative reduction potentials. It is known when irradiated with light the Au-NPs can abstract hydrogen from isopropanol forming Au-H species on the Au-NP surface. Hence, we proposed that the active Au-H species will react with the N=O, N=N, C=O double bonds or epoxide bonds, which are weakened by the interaction with the excited electrons in the Au-NPs, and yield the final reductive products. The reacting power of the Au-H species depends on the energy of the excited electrons in Au-NPs: the higher the electronic energy, the stronger the reduction ability of the Au-H species. This finding demonstrates that we can tune the reduction ability of the photocatalysts by manipulating the irradiation wavelength.

Examination of distracted driving and yellow light running : analysis of simulator data

Driving on an approach to a signalized intersection while distracted is particularly dangerous, as potential vehicular conflicts and resulting angle collisions tend to be severe. Given the prevalence and importance of this particular scenario, the decisions and actions of distracted drivers during the onset of yellow lights are the focus of this study. Driving simulator data were obtained from a sample of 58 drivers under baseline and handheld mobile phone conditions at the University of Iowa - National Advanced Driving Simulator. Explanatory variables included age, gender, cell phone use, distance to stop-line, and speed. Although there is extensive research on drivers’ responses to yellow traffic signals, the examination has been conducted from a traditional regression-based approach, which does not necessary provide the underlying relations and patterns among the sampled data. In this paper, we exploit the benefits of both classical statistical inference and data mining techniques to identify the a priori relationships among main effects, non-linearities, and interaction effects. Results suggest that novice (16-17 years) and young drivers’ (18-25 years) have heightened yellow light running risk while distracted by a cell phone conversation. Driver experience captured by age has a multiplicative effect with distraction, making the combined effect of being inexperienced and distracted particularly risky. Overall, distracted drivers across most tested groups tend to reduce the propensity of yellow light running as the distance to stop line increases, exhibiting risk compensation on a critical driving situation.

Performance of elite seated discus throwers in F30s classes : part I: does whole body positioning matter?

Background: Studies on the relationship between performance and design of the throwing frame have been limited and therefore require further investigation. Objectives: The specific objectives were to provide benchmark information about performance and whole body positioning of male athletes in F30s classes. Study Design: Descriptive analysis. Methods: A total of 48 attempts performed by 12 stationary discus throwers in F33 and F34 classes during seated discus throwing event of 2002 International Paralympic Committee Athletics World Championships were analysed in this study. The whole body positioning included overall throwing posture (i.e. number of points of contact between the thrower and the frame, body position, throwing orientation and throwing side) and lower limb placements (i.e. seating arrangements, points of contact on the both feet, type of attachment of both legs and feet). Results: Three (25%), five (42%), one (8%) and three (25%) athletes used from three to six points of contact, respectively. Seven (58%) and five (42%) athletes threw from a standing or a seated position, respectively. A straddle, a stool or a chair was used by six (50%), four (33%) or two (17%) throwers, respectively. Conclusions: This study provides key information for a better understanding of the interaction between throwing technique of elite seated throwers and their throwing frame.

Interaction of water with the fluorine-covered anatase TiO2(001) surface

The interaction of water with the fluorine-covered (001) surface of anatase titanium dioxide (TiO2) has been studied within the framework of density functional theory (DFT). Our results show that water dissociation is unfavorable due to repulsive interactions between surface fluorine and oxygen. We also found that the reaction of hydrofluoric acid with a surface hydroxyl group to form a surface Ti–F bond is exothermic, while the removal of fluorine from the surface needs additional energy of about half an eV. Therefore, water molecules are predicted to remain intact at the interface with the F-terminated anatase (001).

The influence of oxygenated organic aerosols (OOA) on the oxidative potential of diesel and biodiesel particulate matter

Generally, the magnitude of pollutant emissions from diesel engines running on biodiesel fuel is ultimately coupled to the structure of respective molecules that constitutes the fuel. Previous studies demonstrated the relationship between organic fraction of PM and its oxidative potential. Herein, emissions from a diesel engine running on different biofuels were analysed in more detail to explore the role different organic fractions play in the measured oxidative potential. In this work, a more detailed chemical analysis of biofuel PM was undertaken using a compact Time of Flight Aerosol Mass Spectrometer (c-ToF AMS). This enabled a better identification of the different organic fractions that contribute to the overall measured oxidative potentials. The concentration of reactive oxygen species (ROS) was measured using a profluorescent nitroxide molecular probe 9-(1,1,3,3-tetramethylisoindolin-2-yloxyl-5-ethynyl)-10-(phenylethynyl)anthracene (BPEAnit). Therefore the oxidative potential of the PM, measured through the ROS content, although proportional to the total organic content in certain cases shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS. This highlights the importance of knowing the surface chemistry of particles for assessing their health impacts. It also sheds light onto new aspects of particulate emissions that should be taken into account when establishing relevant metrics for assessing health implications of replacing diesel with alternative fuels.

Regulation of dormancy in barley by blue light and after-ripening : effects on abscisic acid and gibberellin metabolism

White light strongly promotes dormancy in freshly harvested cereal grains, whereas dark and after-ripening have the opposite effect. We have analyzed the interaction of light and after-ripening on abscisic acid (ABA) and gibberellin (GA) metabolism genes and dormancy in barley (Hordeum vulgare ‘Betzes’). Analysis of gene expression in imbibed barley grains shows that different ABA metabolism genes are targeted by white light and after-ripening. Of the genes examined, white light promotes the expression of an ABA biosynthetic gene, HvNCED1, in embryos. Consistent with this result, enzyme-linked immunosorbent assays show that dormant grains imbibed under white light have higher embryo ABA content than grains imbibed in the dark. After-ripening has no effect on expression of ABA biosynthesis genes, but promotes expression of an ABA catabolism gene (HvABA8′OH1), a GA biosynthetic gene (HvGA3ox2), and a GA catabolic gene (HvGA2ox3) following imbibition. Blue light mimics the effects of white light on germination, ABA levels, and expression of GA and ABA metabolism genes. Red and far-red light have no effect on germination, ABA levels, or HvNCED1. RNA interference experiments in transgenic barley plants support a role of HvABA8′OH1 in dormancy release. Reduced HvABA8′OH1 expression in transgenic HvABA8′OH1 RNAi grains results in higher levels of ABA and increased dormancy compared to nontransgenic grains.

Making arrangements in talk-in-interaction

Arrangement-making is understood to be a ‘closing-relevant action’ (Schegloff & Sacks 1973), but little attention has been given to how people arrive at mutually acceptable plans for the future. Telephone conversations between clients and staff of Community and Home Care (CHC) services were studied to identify how arrangements for future services were made. A recurrent sequence was observed in which clients were informed of future arrangement and were prompted to reply with ‘response solicitation’ (Jefferson 1981). Response solicitations were observed at two points: either tagged to the end of an informing, or following a recipient’s response to the informing. We show how response solicitations are routinely used in instances where recipients have some discretion in relation to the arrangement under discussion. They are a means by which an informing party can display to their interlocutor that they, as recipient, have some discretion to exercise in the matter. These findings are discussed with reference to prior research on arrangement-making in other settings, which suggests the general nature of this practice.

Disentangling fluxes of energy and matter in plasma-surface interactions : effect of process parameters

The possibility to discriminate between the relative importance of the fluxes of energy and matter in plasma-surface interaction is demonstrated by the energy flux measurements in low-temperature plasmas ignited by the radio frequency discharge (power and pressure ranges 50-250 W and 8-11.5 Pa) in Ar, Ar+ H2, and Ar+ H2 + CH4 gas mixtures typically used in nanoscale synthesis and processing of silicon- and carbon-based nanostructures. It is shown that by varying the gas composition and pressure, the discharge power, and the surface bias one can effectively control the surface temperature and the matter supply rates. The experimental findings are explained in terms of the plasma-specific reactions in the plasma bulk and on the surface.

Efficiency of lexical access in children with autism spectrum disorders : does modality matter?

The provision of visual support to individuals with an autism spectrum disorder (ASD) is widely recommended. We explored one mechanism underlying the use of visual supports: efficiency of language processing. Two groups of children, one with and one without an ASD, participated. The groups had comparable oral and written language skills and nonverbal cognitive abilities. In two semantic priming experiments, prime modality and prime–target relatedness were manipulated. Response time and accuracy of lexical decisions on the spoken word targets were measured. In the first uni-modal experiment, both groups demonstrated significant priming effects. In the second experiment which was cross-modal, no effect for relatedness or group was found. This result is considered in the light of the attentional capacity required for access to the lexicon via written stimuli within the developing semantic system. These preliminary findings are also considered with respect to the use of visual support for children with ASD.

Temporal characteristics of melanopsin inputs to the human pupil light reflex

Rods, cones and melanopsin containing intrinsically photosensitive retinal ganglion cells (ipRGCs) operate in concert to regulate pupil diameter. The temporal properties of intrinsic ipRGC signalling are distinct to those of rods and cones, including longer latencies and sustained signalling after light offset. We examined whether the melanopsin mediated post-illumination pupil response (PIPR) and pupil constriction were dependent upon the inter-stimulus interval (ISI) between successive light pulses and the temporal frequency of sinusoidal light stimuli. Melanopsin excitation was altered by variation of stimulus wavelength (464 nm and 638 nm lights) and irradiance (11.4 and 15.2 log photons cm(-2) s(-1)). We found that 6s PIPR amplitude was independent of ISI and temporal frequency for all melanopsin excitation levels, indicating complete summation. In contrast to the PIPR, the maximum pupil constriction increased with increasing ISI with high and low melanopsin excitation, but time to minimum diameter was slower with high melanopsin excitation only. This melanopsin response to briefly presented pulses (16 and 100 ms) slows the temporal response of the maximum pupil constriction. We also demonstrate that high melanopsin excitation attenuates the phasic peak-trough pupil amplitude compared to conditions with low melanopsin excitation, indicating an interaction between inner and outer retinal inputs to the pupil light reflex. We infer that outer retina summation is important for rapidly controlling pupil diameter in response to short timescale fluctuations in illumination and may occur at two potential sites, one that is presynaptic to extrinsic photoreceptor input to ipRGCs, or another within the pupil control pathway if ipRGCs have differential temporal tuning to extrinsic and intrinsic signalling.

A review of iron species for visible-light photocatalytic water purification

Iron species are one of the least toxic and least expensive substances that are photocatalytic in the visible region of the spectrum. Therefore, this article focuses on iron-based photocatalysts sensitive to visible light. Photo-Fenton reactions are considered with respect to those assisted by and involve the in situ production of H2O2. The possible role that photoactive iron species play by interacting with natural organic matter in water purification in the natural environment is considered. The review also considered photosensitization by phthalocyanines and the potential role that layered double hydroxides may have not only as catalyst supports but also as photosensitizers themselves. Finally, photocatalytic disinfection of water is discussed, and the desirability of standardized metrics and experimental conditions to assist in the comparative evaluation of photocatalysts is highlighted.

Projecting the new world city: The city as spectacle in an urban light festival

As a precursor to the 2014 G20 Leaders’ Summit held in Brisbane, Australia, the Queensland Government sponsored a program of G20 Cultural Celebrations, designed to showcase the Summit’s host city. The cultural program’s signature event was the Colour Me Brisbane festival, a two-week ‘citywide interactive light and projection installations’ festival that was originally slated to run from 24 October to 9 November, but which was extended due to popular demand to conclude with the G20 Summit itself on 16 November. The Colour Me Brisbane festival comprised a series projection displays that promoted visions of the city’s past, present, and future at landmark sites and iconic buildings throughout the city’s central business district and thus transformed key buildings into forms of media architecture. In some instances the media architecture installations were interactive, allowing the public to control aspects of the projections through a computer interface situated in front of the building; however, the majority of the installations were not interactive in this sense. The festival was supported by a website that included information regarding the different visual and interactive displays and links to social media to support public discussion regarding the festival (Queensland Government 2014). Festival-goers were also encouraged to follow a walking-tour map of the projection sites that would take them on a 2.5 kilometre walk from Brisbane’s cultural precinct, through the city centre, concluding at parliament house. In this paper, we investigate the Colour Me Brisbane festival and the broader G20 Cultural Celebrations as a form of strategic placemaking—designed, on the one hand, to promote Brisbane as a safe, open, and accessible city in line with the City Council’s plan to position Brisbane as a ‘New World City’ (Brisbane City Council 2014). On the other hand, it was deployed to counteract growing local concerns and tensions over the disruptive and politicised nature of the G20 Summit by engaging the public with the city prior to the heightened security and mobility restrictions of the Summit weekend. Harnessing perspectives from media architecture (Brynskov et al. 2013), urban imaginaries (Cinar & Bender 2007), and social media analysis, we take a critical approach to analysing the government-sponsored projections, which literally projected the city onto itself, and public responses to them via the official, and heavily promoted, social media hashtags (#colourmebrisbane and #g20cultural). Our critical framework extends the concepts of urban phantasmagoria and urban imaginaries into the emerging field of media architecture to scrutinise its potential for increased political and civic engagement. Walter Benjamin’s concept of phantasmagoria (Cohen 1989; Duarte, Firmino, & Crestani 2014) provides an understanding of urban space as spectacular projection, implicated in commodity and techno-culture. The concept of urban imaginaries (Cinar & Bender 2007; Kelley 2013)—that is, the ways in which citizens’ experiences of urban environments are transformed into symbolic representations through the use of imagination—similarly provides a useful framing device in thinking about the Colour Me Brisbane projections and their relation to the construction of place. Employing these critical frames enables us to examine the ways in which the installations open up the potential for multiple urban imaginaries—in the sense that they encourage civic engagement via a tangible and imaginative experience of urban space—while, at the same time, supporting a particular vision and way of experiencing the city, promoting a commodified, sanctioned form of urban imaginary. This paper aims to dissect the urban imaginaries intrinsic to the Colour Me Brisbane projections and to examine how those imaginaries were strategically deployed as place-making schemes that choreograph reflections about and engagement with the city.

Gender-specific differences of interaction between obesity and air pollution on stroke and cardiovascular diseases in Chinese adults from a high pollution range area: A large population based cross sectional study

Background Little information exists regarding the interaction effects of obesity with long-term air pollution exposure on cardiovascular diseases (CVDs) and stroke in areas of high pollution. The aim of the present study is to examine whether obesity modifies CVD-related associations among people living in an industrial province of northeast China. Methods We studied 24,845 Chinese adults, aged 18 to 74 years old, from three Northeastern Chinese cities in 2009 utilizing a cross-sectional study design. Body weight and height were measured by trained observers. Overweight and obesity were defined as a body mass index (BMI) between 25–29.9 and ≥ 30 kg/m2, respectively. Prevalence rate and related risk factors of cardiovascular and cerebrovascular diseases were investigated by a questionnaire. Three-year (2006–2008) average concentrations of particulate matter (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were measured by fixed monitoring stations. All the participants lived within 1 km of air monitoring sites. Two-level logistic regression (personal level and district-specific pollutant level) was used to examine these effects, controlling for covariates. Results We observed significant interactions between exposure and obesity on CVDs and stroke. The associations between annual pollutant concentrations and CVDs and stroke were strongest in obese subjects (OR 1.15–1.47 for stroke, 1.33–1.59 for CVDs), less strong in overweight subjects (OR 1.22–1.35 for stroke, 1.07–1.13 for CVDs), and weakest in normal weight subjects (OR ranged from 0.98–1.01 for stroke, 0.93–1.15 for CVDs). When stratified by gender, these interactions were significant only in women. Conclusions Study findings indicate that being overweight and obese may enhance the effects of air pollution on the prevalence of CVDs and stroke in Northeastern metropolitan China. Further studies will be needed to investigate the temporality of BMI relative to exposure and onset of disease.

Genetics of white matter development: A DTI study of 705 twins and their siblings aged 12 to 29

White matter microstructure is under strong genetic control, yet it is largely unknown how genetic influences change from childhood into adulthood. In one of the largest brain mapping studies ever performed, we determined whether the genetic control over white matter architecture depends on age, sex, socioeconomic status (SES), and intelligence quotient (IQ). We assessed white matter integrity voxelwise using diffusion tensor imaging at high magnetic field (4-Tesla), in 705 twins and their siblings (age range 12-29; 290. M/415. F). White matter integrity was quantified using a widely accepted measure, fractional anisotropy (FA). We fitted gene-environment interaction models pointwise, to visualize brain regions where age, sex, SES and IQ modulate heritability of fiber integrity. We hypothesized that environmental factors would start to outweigh genetic factors during late childhood and adolescence. Genetic influences were greater in adolescence versus adulthood, and greater in males than in females. Socioeconomic status significantly interacted with genes that affect fiber integrity: heritability was higher in those with higher SES. In people with above-average IQ, genetic factors explained over 80% of the observed FA variability in the thalamus, genu, posterior internal capsule, and superior corona radiata. In those with below-average IQ, however, only around 40% FA variability in the same regions was attributable to genetic factors. Genes affect fiber integrity, but their effects vary with age, sex, SES and IQ. Gene-environment interactions are vital to consider in the search for specific genetic polymorphisms that affect brain integrity and connectivity.

Decisions and actions of distracted drivers at the onset of yellow light

Driving on an approach to a signalized intersection while distracted is relatively risky, as potential vehicular conflicts and resulting angle collisions tend to be relatively more severe compared to other locations. Given the prevalence and importance of this particular scenario, the objective of this study was to examine the decisions and actions of distracted drivers during the onset of yellow lights. Driving simulator data were obtained from a sample of 69 drivers under baseline and handheld cell phone conditions at the University of Iowa – National Advanced Driving Simulator. Explanatory variables included age, gender, cell phone use, distance to stop-line, and speed. Although there is extensive research on drivers’ responses to yellow traffic signals, the examinations have been conducted from a traditional regression-based approach, which do not necessary provide the underlying relations and patterns among the sampled data. In this paper, we exploit the benefits of both classical statistical inference and data mining techniques to identify the a priori relationships among main effects, non-linearities, and interaction effects. Results suggest that the probability of yellow light running increases with the increase in driving speed at the onset of yellow. Both young (18–25 years) and middle-aged (30–45 years) drivers reveal reduced propensity for yellow light running whilst distracted across the entire speed range, exhibiting possible risk compensation during this critical driving situation. The propensity for yellow light running for both distracted male and female older (50–60 years) drivers is significantly higher. Driver experience captured by age interacts with distraction, resulting in their combined effect having slower physiological response and being distracted particularly risky.