Photocatalytic degradation of an organophosphorus compound by porous Au- and WO3- modified TiO2

Organophosphorus (OP) compounds are highly toxic substances that are often used as chemical warfare agents and pesticides. OP pesticides are the most widely used class of pesticide in the world, and due to their ubiquity, the contamination of agricultural runoff by OP pesticides has become a problem of global concern. One of the more attractive solutions that has been proposed is the use of photocatalytic degradation to decontaminate affected water supplies. In the present work, the visible-light photocatalytic activity of a series of porous Au-WO3-TiO2 photocatalysts with variable concentrations of Au (0, 1, 3, and 5 weight percent) synthesized using mesoporous SiO2 as a template was evaluated in the aqueous degradation reaction of an OP agent, dimethyl methylphosphonate (DMMP). The Au and WO3 were added to the catalysts using sonochemical deposition and incipient wetness impregnation, respectively. The photocatalytic activity of the ternary Au-WO3-TiO2 series was compared to that of a WO3-free series of Au-TiO2 catalysts with comparable Au loadings. The catalysts were characterized by scanning electron microscopy (SEM), powder x-ray diffractometry (PXRD), and N2-physisorption. The SEM and N2-physisorption analyses indicated the Au-TiO2 and Au-WO3-TiO2 particles had high surface areas of 135 m2 g-1 and 100 m2 g-1, respectively, with particle diameters of 1-3 μm. No crystalline WO3 was detected on the WO3-containing species, indicating the formation of a monolayer of WO3 on the surface of the TiO2. The sonochemically deposited gold nanoparticles (NPs) were found to be 3-10 nm in diameter. The photocatalytic degradation of DMMP was monitored by quantitative GCMS analysis. The independent addition of Au NPs or WO3 to the surface of the TiO2 did not significantly affect the total degradation of DMMP after 30 hours of irradiation relative to unmodified TiO2, however the presence of both Au and WO3 on the surface of the TiO2 significantly increased the total degradation of DMMP after 30 hours, reaching the detection limit for the 1 and 3 weight percent catalysts. It was found that the photocatalytic activity of the Au-WO3-TiO2 catalysts was not significantly influenced by the weight percent Au for the concentrations studied

Thermoelectric properties of AgGaTe2_2 and related chalcopyrite structure materials

We present an analysis of the potential thermoelectric performance of p-type AgGaTe$_{2}$, which has already shown a $ZT$ of 0.8 with partial optimization, and observe that the same band structure features, such as a mixture of light and heavy bands and isotropic transport, that lead to this good performance are present in certain other ternary chalcopyrite structure semiconductors. We find that optimal performance of AgGaTe$_2$ will be found for hole concentrations between 4 $\times 10^{19}$ and 2 $\times 10^{20}$cm$^{-3}$ at 900 K, and 2 $\times 10^{19}$ and 10$^{20}$ cm$^{-3}$ at 700 K, and that certain other chalcopyrite semiconductors might show good thermoelectric performance at similar doping ranges and temperatures if not for higher lattice thermal conductivity

Immune- and nonimmune-compartment-specific interferon responses are critical determinants of herpes simplex virus-induced generalized infections and acute liver failure

The interferon (IFN) response to viral pathogens is critical for host survival. In humans and mouse models, defects in IFN responses can result in lethal herpes simplex virus 1 (HSV-1) infections, usually from encephalitis. Although rare, HSV-1 can also cause fulminant hepatic failure, which is often fatal. Although herpes simplex encephalitis has been extensively studied, HSV-1 generalized infections and subsequent acute liver failure are less well understood. We previously demonstrated that IFN-αβγR-/- mice are exquisitely susceptible to liver infection following corneal infection with HSV-1. In this study, we used bone marrow chimeras of IFN-αβγR-/- (AG129) and wild-type (WT; 129SvEv) mice to probe the underlying IFN-dependent mechanisms that control HSV-1 pathogenesis. After infection, WT mice with either IFN-αβγR-/- or WT marrow exhibited comparable survival, while IFN-αβγR-/- mice with WT marrow had a significant survival advantage over their counterparts with IFN-αβγR-/- marrow. Furthermore, using bioluminescent imaging to maximize data acquisition, we showed that the transfer of IFN-competent hematopoietic cells controlled HSV-1 replication and damage in the livers of IFN-αβγR-/- mice. Consistent with this, the inability of IFN-αβγR-/- immune cells to control liver infection in IFN-αβγR-/- mice manifested as profoundly elevated aspartate transaminase (AST) and alanine transaminase (ALT) levels, indicative of severe liver damage. In contrast, IFN-αβγR-/-mice receiving WT marrow exhibited only modest elevations of AST and ALT levels. These studies indicate that IFN responsiveness of the immune system is a major determinant of viral tropism and damage during visceral HSV infections

Bayesian Optimal Design for Ordinary Differential Equation Models

Bayesian optimal design is considered for experiments where it is hypothesised that the responses are described by the intractable solution to a system of non-linear ordinary differential equations (ODEs). Bayesian optimal design is based on the minimisation of an expected loss function where the expectation is with respect to all unknown quantities (responses and parameters). This expectation is typically intractable even for simple models before even considering the intractability of the ODE solution. New methodology is developed for this problem that involves minimising a smoothed stochastic approximation to the expected loss and using a state-of-the-art stochastic solution to the ODEs, by treating the ODE solution as an unknown quantity. The methodology is demonstrated on three illustrative examples and a real application involving estimating the properties of human placentas

Is South Florida the New Southern California?: Carl Hiaasen\u27s Dystopian Paradise

Florida and California have from their entry into American culture been considered by writers to be enchanted states, the places to which Americans can escape to a more exotic reality than is represented by the colder North and East. As early as the American Revolution, then-Spanish Florida was known for its unspoiled terrain and its lush beauty. Harriet Beecher Stowe extolled its exotic qualities, while Stephen Crane wrote of the contrast between the harsh outside world and the escapist qualities of the state. California, by contrast, has been seen as a paradise, a found Eden, and like Florida, a place whose beauty never palls since the Gold Rush brought Americans west in the 1840s. While Florida was tropical, writers saw California as Mediterranean. Still, other writers found that even the natural beauty could not mask the American civilization that intruded on it, and this began a debunking discourse in reference to these two exotic regions.

Observation of PT phase transition in a simple mechanical system

If a Hamiltonian is PT symmetric, there are two possibilities: Either the eigenvalues are entirely real, in which case the Hamiltonian is said to be in an unbroken-PT-symmetric phase, or else the eigenvalues are partly real and partly complex, in which case the Hamiltonian is said to be in a broken-PT-symmetric phase. As one varies the parameters of the Hamiltonian, one can pass through the phase transition that separates the unbroken and broken phases. This transition has recently been observed in a variety of laboratory experiments. This paper explains the phase transition in a simple and intuitive fashion and then describes an extremely elementary experiment in which the phase transition is easily observed.Comment: 9 pages, 9 figure

On the ballot: how electoral procedures shape the work of Members of the Scottish Parliament

The electoral system by which members of parliament are elected shapes how legislators perceive their roles. Furthermore, write David C.W. Parker and Caitlyn M. Richter, in the case of the Scottish Parliament, both the electoral system and the change implemented prior to the 2007 election, whereby candidate names were removed from party-list ballots, have an impact on how Members of the Scottish Parliament spend their time and resources

Curvilinear ridges and related features in southwest Cydonia Mensae, Mars

Examined is a region on Mars in southwest Cydonia Mensae (32 deg lat., 17 deg long.) just northwest of the lowland/upland boundary escarpment. The dominant morphological features in this region are the clusters of large massifs and plateau outliers (PI), knobby material (K), and smooth lowland plains (Ps). Surrounding the clusters and linking many isolated knobs is a system of curvilinear ridges and arcuate terrain boundaries which tend to separate the massifs and knobs from the smooth plains. Curvilinear ridges are arcuate to nearly linear and smoother in plan than wrinkle ridges and show no apparent correlation with regional structural grain. They are typically 5 to 10 km long but can range from as little as 2 or 3 km to greater than 50 km long. The widths vary from about 100 m to as much as 2 km. Curvilinear ridges are most numerous within 100 km of the lowland/upland boundary escarpment and are associated with massifs and knobby terrain. Arcuate terrain boundaries appear between units of different apparent albedo or arcuate breaks in slope

Geomorphic evidence for ancient seas in west Deuteronilus Mensae, Mars-2: From very high resolution Viking Orbiter images

Very high resolution Viking Orbiter images of the Martian surface, though rare, make it possible to examine specific areas at image scales approaching those of high altitude terrestrial aerial photographs. Twenty three clear images lie within west Deuteronilus Mensae. The northernmost images which constitute an almost unbroken mosaic of the west wall of a long fingerlike canyon are examined. Morphological details on the plateau surface within zone B, not detectable at low resolution, make it possible to divide the zone into two distinct subzones separated by an east-west escarpment. The morphology of the canyon floor is described in detail

Geomorphic evidence for ancient seas in west Deuteronilus Mensae, Mars-1: Regional geomorphology

The fretted terrain in west Deuteronilus Mensae consists of extensive cratered upland penninsulas or isolated plateaus cut by long, finger-like canyons typically 10 to 20 km wide and upwards of 300 km long. The longest of these canyons trend roughly north-south to north-northeast, which may reflect some local structural and/or topographic control. At least three geomorphic zones roughly parallel to the lowland/upland boundary, suggestive of increasing modification northward, can be recognized on the fretted region of the region. The southern-most zone (zone A) consists of sharply defined fretted terrain. The middle zone (zone B) consists of well defined fretted terrain in which the plateau surfaces appear smoother, with a somewhat darker and much less varied albedo surface than those of zone A. The northern-most zone (zone C) consists of rounded or softened fretted terrain. The zones were interpreted as surface exposures of successively lower stratigraphic units