176 research outputs found
Study of intercalation and deintercalation of Na_xCoO_2 yH_2O single crystals
Single crystals of NaxCoO2 with beta-phase (x=0.55, 0.60 and 0.65),
alpha'-phase (x=0.75) and alpha-phase (x=0.9, 1.0) have been grown by the
floating zone technique. The Na-extraction and hydration were carried out for
the alpha'-sample to get superconducting phase of NaxCoO2.yH2O (x~0.3, y~1.3).
Hydrated single crystals exhibit cracked layers perpendicular to the c-axis due
to a large expansion when the water is inserted into the structure. A study of
intercalation/deintercalation was performed to determine the stability of the
hydrated phase and effects of hydration on the structure of the compound. X-ray
diffraction and Thermogravimetric experiments are used to monitor the process
of water molecules accommodated in and removed from the crystal lattice. The
initial intercalation process takes place with two-water molecules
corresponding to y=0.6) inserted in a formula unit, followed by a group of four
(y=1.3) to form a cluster of Na(H2O)4. Thermogravimetric analysis suggests that
the deintercalation occurs with the removal of the water molecules one by one
from the hydrated cluster at elevated temperatures of approximately 50, 100,
200 and 300 C, respectively. Our investigations reveal that the hydration
process is dynamic and that water molecule inter- and deintercalation follow
different reaction paths in an irreversible way.Comment: 15 pages, 6 figures, figures with higher resolution by email request
from the corresponding autho
Comparative Evaluation of Nanofibrous Scaffolding for Bone Regeneration in Critical-Size Calvarial Defects
In a previous study we found that nanofibrous poly(l-lactic acid) (PLLA) scaffolds mimicking collagen fibers in size were superior to solid-walled scaffolds in promoting osteoblast differentiation and bone formation in vitro. In this study we used an in vivo model to confirm the biological properties of nanofibrous PLLA scaffolds and to evaluate how effectively they support bone regeneration against solid-walled scaffolds. The scaffolds were implanted in critical-size defects made on rat calvarial bones. Compared with solid-walled scaffolds, nanofibrous scaffolds supported substantially more new bone tissue formation, which was confirmed by micro-computed tomography measurement and von Kossa staining. Goldner's trichrome staining showed abundant collagen deposition in nanofibrous scaffolds but not in the control solid-walled scaffolds. The cells in these scaffolds were immuno-stained strongly for Runx2 and bone sialoprotein (BSP). In contrast, solid-walled scaffolds implanted in the defects were stained weakly with trichrome, Runx2, and BSP. These in vivo results demonstrate that nanofibrous architecture enhances osteoblast differentiation and bone formation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78127/1/ten.tea.2008.0433.pd
Notes on dark energy interacting with dark matter and unparticle in loop quantum cosmology
We investigate the behavior of dark energy interacting with dark matter and
unparticle in the framework of loop quantum cosmology. In four toy models, we
study the interaction between the cosmic components by choosing different
coupling functions representing the interaction. We found that there are only
two attractor solutions namely dark energy dominated and dark matter dominated
Universe. The other two models are unstable, as they predict either a dark
energy filled Universe or one completely devoid of it.Comment: 9 pages, 10 figures. v2: Minor revisions, matches published versio
Long-term underwater camera surveillance for monitoring and analysis of fish populations
Long-term monitoring of the underwater environment is still labour intensive work. Using underwater surveillance cameras to monitor this environment has the potential advantage to make the task become less labour intensive. Also, the obtained data can be stored making the research reproducible. In this work, a system to analyse long-term underwater camera footage (more than 3 years of 12 hours a day underwater camera footage from 10 cameras) is described. This system uses video processing software to detect and recognise fish species. This footage is processed on supercomputers, which allow marine biologists to request automatic processing on these videos and afterwards analyse the
results using a web-interface that allows them to display counts of fish species in the camera footage
Observational constraint on generalized Chaplygin gas model
We investigate observational constraints on the generalized Chaplygin gas
(GCG) model as the unification of dark matter and dark energy from the latest
observational data: the Union SNe Ia data, the observational Hubble data, the
SDSS baryon acoustic peak and the five-year WMAP shift parameter. It is
obtained that the best fit values of the GCG model parameters with their
confidence level are ()
, ()
. Furthermore in this model, we can see that the
evolution of equation of state (EOS) for dark energy is similar to quiessence,
and its current best-fit value is with the confidence
level .Comment: 9 pages, 5 figure
Fish4Knowledge- large scale coral reef fish monitoring using undersea computer vision methods
Prevalence of Type 2 Diabetes among Newly Detected Pulmonary Tuberculosis Patients in China: A Community Based Cohort Study
Background: Patients with type 2 diabetes (DM) have a higher risk of developing pulmonary tuberculosis (PTB); moreover, DM co-morbidity in PTB is associated with poor PTB treatment outcomes. Community based prevalence data on DM and prediabetes (pre-DM) among TB patients is lacking, particularly from the developing world. Therefore we conducted a prospective study to investigate the prevalence of DM and pre-DM and evaluated the risk factors for the presence of DM among newly detected PTB patients in rural areas of China. Methods and Findings: In a prospective community based study carried out from 2010 to 2012, a representative sample of 6382 newly detected PTB patients from 7 TB clinics in Linyi were tested for DM. A population of 6674 non-TB controls from the same community was similarly tested as well. The prevalence of DM in TB patients (6.3%) was higher than that in non-TB controls (4.7%, p = 10000 RMB yuan) were positively associated and frequent outdoor activity was negatively associated with DM in PTB patients. Conclusions: The prevalence of DM in PTB patients was higher than in non-TB controls with a 3 fold higher adjusted odds ratio of having DM. Given the increasing DM prevalence and still high burden of TB in China, this association may represent a new public health challenge concerning the prevention and treatment of both diseases
Statefinder Diagnostic for Dilaton Dark Energy
Statefinder diagnostic is a useful method which can differ one dark energy
model from the others. The Statefinder pair is algebraically related
to the equation of state of dark energy and its first time derivative. We apply
in this paper this method to the dilaton dark energy model based on Weyl-Scaled
induced gravitational theory. We investigate the effect of the coupling between
matter and dilaton when the potential of dilaton field is taken as the Mexican
hat form. We find that the evolving trajectory of our model in the
diagram is quite different from those of other dark energy models.Comment: 6 pages, 4 figures, type errors corrected, reference no. changed,
accepted by Astrophysics and Space Scienc
Biosorption of heavy metal ions (Pb, Cu, and Cd) from aqueous solutions by the Marine Alga Sargassum sp. in single- And multiple-metal systems
10.1021/ie0615786Industrial and Engineering Chemistry Research4682438-2444IECR
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