361 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
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
Helicobacter pylori infection and gastroduodenal diseases in Vietnam: a cross-sectional, hospital-based study
<p>Abstract</p> <p>Background</p> <p>The rate of <it>H. pylori </it>infection in Vietnam is reportedly high, but the spectrum of <it>H. pylori</it>-associated gastroduodenal diseases has not been systematically investigated. Moreover, despite the similarities of ethnicity and diet, the age-standardized incidence rate of gastric cancer in the northern city of Hanoi is higher than that in the southern city of Ho Chi Minh, but the reason for this phenomenon is unknown. The virulence of Vietnamese <it>H. pylori </it>has also not been investigated in detail.</p> <p>Methods</p> <p>Individuals undergoing esophagogastroduodenoscopy were randomly recruited. <it>H. pylori </it>infection status was determined based on the combined results of culture, histology, immunohistochemistry, rapid urine test and serum ELISA. Peptic ulcer (PU) and gastroesophageal reflux disease was diagnosed by endoscopy, and chronic gastritis was determined histologically. <it>H. pylori </it>virulence factors were investigated by PCR and sequencing.</p> <p>Results</p> <p>Among the examined patients, 65.6% were infected with <it>H. pylori</it>. The prevalence of infection was significantly higher in those over 40 years of age than in those aged ≤40. Chronic gastritis was present in all <it>H. pylori</it>-infected individuals, 83.1% of whom had active gastritis, and 85.3% and 14.7% had atrophy and intestinal metaplasia, respectively. PU was present in 21% of infected patients, whereas its incidence was very low in non-infected individuals. The prevalence of PU was significantly higher in Hanoi than in Ho Chi Minh. The prevalence of <it>vacA m1</it>, which has been identified as an independent risk factor for PU in Vietnam, was significantly higher among <it>H. pylori </it>isolates from Hanoi than among those from Ho Chi Minh.</p> <p>Conclusions</p> <p><it>H. pylori </it>infection is common in Vietnam and is strongly associated with PU, active gastritis, atrophy and intestinal metaplasia. <it>vacA m1 </it>is associated with an increased risk for PU and might contribute to the difference in the prevalence of PU and gastric cancer between Hanoi and Ho Chi Minh.</p
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
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