425 research outputs found
Effect of cation size variance on spin and orbital order in Eu(LaY)VO
We have investigated the -ion ( = rare earth or Y) size variance effect
on spin/orbital order in Eu(LaY)VO. The
size variance disturbs one-dimensional orbital correlation in -type
spin/-type orbital ordered states and suppresses this spin/orbital order. In
contrast, it stabilizes the other spin/orbital order. The results of neutron
and resonant X-ray scattering denote that in the other ordered phase, the
spin/orbital patterns are -type/-type, respectively.Comment: 4 pages, 4 figures, accepted to Rapid Communication in Physical
Review
Optimization of Monte-Carlo calculations of the effective potential
We study Monte Carlo calculations of the effective potential for a scalar
field theory using three techniques. One of these is a new method proposed and
tested for the first time. In each case we extract the renormalised quantities
of the theory. The system studied in our calculations is a one component
model in two dimensions. We apply these methods to both the weak and
strong coupling regime. In the weak coupling regime we compare our results for
the renormalised quantities with those obtained from two-loop lattice
perturbation theory. Our results are verified in the strong coupling regime
through comparison with the strong coupling expansion. We conclude that
effective potential methods, when suitably chosen, can be accurate tools in
calculations of the renormalised parameters of scalar field theories.Comment: 26 pages of LaTeX, uses psfig.sty with 6 figures. Entire manuscript
available as a postscript file via WWW at
http://www.physics.adelaide.edu.au/theory/papers/ADP-97-13.T250-abs.html or
via anonymous ftp at
ftp://bragg.physics.adelaide.edu.au/pub/theory/ADP-97-13.T250.p
In Silico-Based Drug Discovery Targeting HGF-Met
Division of Tumor Dynamics and Regulatio
The Direct Synthesis of H <sub>2</sub> O <sub>2</sub> Using TS-1 Supported Catalysts
In this study we show that using gold palladium nanoparticles supported on a commercial titanium silicate (TS‐1) prepared using a wet co‐impregnation method it is possible to produce hydrogen peroxide from molecular H2 and O2 via the direct synthesis reaction. The effect of Au: Pd ratio and calcination temperature is evaluated as well as the role of platinum addition to the AuPd supported catalysts. The effect of platinum addition to gold‐palladium nanoparticles is observed to result in a significant improvement in catalytic activity and selectivity to hydrogen peroxide with detailed characterisation indicating this is a result of selectively tuning the ratio of palladium oxidation states
Highly efficient catalytic production of oximes from ketones using in situ-generated H<sub>2</sub>O<sub>2</sub>
The ammoximation of cyclohexanone using preformed hydrogen peroxide (H2O2) is currently applied commercially to produce cyclohexanone oxime, an important feedstock in nylon-6 production. We demonstrate that by using supported gold-palladium (AuPd) alloyed nanoparticles in conjunction with a titanium silicate-1 (TS-1) catalyst, H2O2 can be generated in situ as needed, producing cyclohexanone oxime with >95% selectivity, comparable to the current industrial route. The ammoximation of several additional simple ketones is also demonstrated. Our approach eliminates the need to transport and store highly concentrated, stabilized H2O2, potentially achieving substantial environmental and economic savings. This approach could form the basis of an alternative route to numerous chemical transformations that are currently dependent on a combination of preformed H2O2 and TS-1, while allowing for considerable process intensification
Thermodynamics of heterogeneous crystal nucleation in contact and immersion modes
One of most intriguing problems of heterogeneous crystal nucleation in
droplets is its strong enhancement in the contact mode (when the foreign
particle is presumably in some kind of contact with the droplet surface)
compared to the immersion mode (particle immersed in the droplet). Many
heterogeneous centers have different nucleation thresholds when they act in
contact or immersion modes, indicating that the mechanisms may be actually
different for the different modes. Underlying physical reasons for this
enhancement have remained largely unclear. In this paper we present a model for
the thermodynamic enhancement of heterogeneous crystal nucleation in the
contact mode compared to the immersion one. To determine if and how the surface
of a liquid droplet can thermodynamically stimulate its heterogeneous
crystallization, we examine crystal nucleation in the immersion and contact
modes by deriving and comparing with each other the reversible works of
formation of crystal nuclei in these cases. As a numerical illustration, the
proposed model is applied to the heterogeneous nucleation of Ih crystals on
generic macroscopic foreign particles in water droplets at T=253 K. Our results
show that the droplet surface does thermodynamically favor the contact mode
over the immersion one. Surprisingly, our numerical evaluations suggest that
the line tension contribution to this enhancement from the contact of three
water phases (vapor-liquid-crystal) may be of the same order of magnitude as or
even larger than the surface tension contribution
Chromogenic detection of yam mosaic virus by closed-tube reverse transcription loop-mediated isothermal amplification (CT-RT-LAMP)
A closed-tube reverse transcription loop-mediated isothermal amplification (CT-RT-LAMP) assay was developed for the detection of yam mosaic virus (YMV, genus Potyvirus) infecting yam (Dioscorea spp.). The assay uses a set of six oligonucleotide primers targeting the YMV coat protein region, and the amplification products in YMV-positive samples are visualized by chromogenic detection with SYBR Green I dye. The CT-RT-LAMP assay detected YMV in leaf and tuber tissues of infected plants. The assay is 100 times more sensitive in detecting YMV than standard RT-PCR, while maintaining the same specificity
Gastrointestinal Stromal Tumor Mimicking Arteriovenous Malformation of the Jejunum
There have been case reports of small intestinal gastrointestinal stromal tumors (GISTs) complicated with arteriovenous malformation (AVM) and angiodysplasia and exhibiting intense tumor staining. Herein we report a GIST of the small intestine that showed tumor staining and early venous return on imaging studies, and so the patient was suspected to have AVM. A 62-year-old male presented with intermittent pain in the left abdominal region. Contrast-enhanced computed tomography revealed a 15-mm-long spindle-shaped mass showing intense tumor staining and early venous return through the jejunal vein. In the arterial phase, the attenuation value of the tumor was 250 Hounsfield units. Color Doppler ultrasonography simultaneously delineated vessels extending from the serosal side and turbulent signals showing a mosaic pattern in the tumor. On angiography, intense staining was observed in the peripheral part of the second branch of the jejunal artery. Although these findings suggested AVM, the tumor was diagnosed as a GIST based on pathological examination of the resected specimens. In this case, no AVM or change in vascular density was noted despite the careful examination of pathological specimens, and the cause of the tumor staining remained unknown
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