3,962 research outputs found
The multifragmentation of spectator matter
We present the first microscopic calculation of the spectator fragmentation
observed in heavy ion reactions at relativistic energies which reproduces the
slope of the kinetic energy spectra of the fragments as well as their
multiplicity, both measured by the ALADIN collaboration. In the past both have
been explained in thermal models, however with vastly different assumptions
about the excitation energy and the density of the system. We show that both
observables are dominated by dynamical processes and that the system does not
pass a state of thermal equilibrium. These findings question the recent
conjecture that in these collisions a phase transition of first order, similar
to that between water and vapor, can be observed.Comment: 7 page
Dynamic van der Waals Theory of two-phase fluids in heat flow
We present a dynamic van der Waals theory. It is useful to study phase
separation when the temperature varies in space. We show that if heat flow is
applied to liquid suspending a gas droplet at zero gravity, a convective flow
occurs such that the temperature gradient within the droplet nearly vanishes.
As the heat flux is increased, the droplet becomes attached to the heated wall
that is wetted by liquid in equilibrium. In one case corresponding to partial
wetting by gas, an apparent contact angle can be defined. In the ther case with
larger heat flux, the droplet completely wets the heated wall expelling liquid.Comment: 6pages, 8figure
Cerebral spectroscopic and oxidative stress studies in patients with schizophrenia who have dangerously violently offended
<p>Abstract</p> <p>Background</p> <p>The aim of this study was to bring together all the results of <it>in vivo </it>studies of ethane excretion and cerebral spectroscopy in patients with schizophrenia who have dangerously seriously violently offended in order to determine the extent to which they shed light on the degree to which the membrane phospholipid hypothesis and the actions of free radicals and other reactive species are associated with cerebral pathophysiological mechanisms in this group of patients.</p> <p>Methods</p> <p>The patients investigated were inpatients from a medium secure unit with a DSM-IV-TR diagnosis of schizophrenia. There was no history of alcohol dependency or any other comorbid psychoactive substance misuse disorder. Expert psychiatric opinion, accepted in court, was that all these patients had violently offended directly as a result of schizophrenia prior to admission. These offences consisted of homicide, attempted murder or wounding with intent to cause grievous bodily harm. Excreted ethane was analyzed and quantified by gas chromatography and mass spectrometry (<it>m</it>/<it>z </it>= 30). 31-phosphorus magnetic resonance spectroscopy data were obtained at a magnetic field strength of 1.5 T using an image-selected <it>in vivo </it>spectroscopy sequence (TR = 10 s; 64 signal averages localized on a 70 × 70 × 70 mm<sup>3 </sup>voxel).</p> <p>Results</p> <p>Compared with age- and sex-matched controls, in the patient group the mean alveolar ethane level was higher (<it>p </it>< 0.0005), the mean cerebral beta-nucleotide triphosphate was lower (<it>p </it>< 0.04) and the mean gamma-nucleotide triphosphate was higher (<it>p </it>< 0.04). There was no significant difference between the two groups in respect of phosphomonoesters, phosphodiesters or broad resonances.</p> <p>Conclusion</p> <p>Our results are not necessarily inconsistent with the membrane phospholipid hypothesis, given that the patients studied suffered predominantly from positive symptoms of schizophrenia. The results suggest that there is increased cerebral mitochondrial oxidative phosphorylation in patients with schizophrenia who have dangerously and seriously violently offended, with an associated increase in oxygen flux and subsequent electron 'leakage' from the electron transport chain leading to the formation of superoxide radicals and other reactive oxygen species. In turn, these reactive species might cause increased lipid peroxidation in neuroglial membranes, thereby accounting for the observation of increased ethane excretion.</p
Physicochemical Properties of Vegetable Proteins: Part VIII- Interaction of Proteins with Iodine in Vapour & Dissolved States
936-94
Physico-chemical Properties of Vegetable Proteins: Part IV- Flocculation of Protein Sols Stabilized at Different pH Values by Electrolytes
530-53
A comparative study of model ingredients: fragmentation in heavy-ion collisions using quantum molecular dynamics model
We aim to understand the role of NN cross-sections, equation of state as well
as different model ingredients such as width of Gaussian, clusterisation range
and different clusterisation algorithms in multifragmentation using quantum
molecular dynamics model. We notice that all model ingredients have sizable
effect on the fragment pattern.Comment: 12 Pages, 4 Figure
Effect of Phosphate Group Addition on the Properties of Denture Base Resins
Statement of problem
Acrylic resins are prone to microbial adherence, especially by Candida albicans. Surface-charged resins alter the ionic interaction between the denture resin and Candida hyphae, and these resins are being developed as a means to reduce microbial colonization on the denture surface. Purpose
The purpose of this study was to investigate the physical and mechanical properties of phosphate-containing polymethyl methacrylate resins for their suitability as a denture material. Material and methods
Using PMMA with cross-linker (Lucitone 199) as a control, 4 experimental groups containing various levels of phosphate with and without cross-linker were generated. The properties examined were impact strength, fracture toughness, wettability (contact angle), and resin bonding ability to denture teeth. Impact strength was tested in the Izod configuration (n=16), and fracture toughness (n=13) was measured using the single-edge notched bend test. Wettability was determined by calculating the contact angle of water on the material surface (n=12), while ISO 1567 was used for bonding ability (n=12). The data were analyzed by 1- and 2-way ANOVA (α=.05). Results
A trend of increased hydrophilicity, as indicated by lower contact angle, was observed with increased concentrations of phosphate. With regard to the other properties, no significant differences were found when compared with the control acrylic resin. Conclusions
No adverse physical effect due to the addition of a phosphate-containing monomer was found in the acrylic denture resins. Additional mechanical and physical properties, biocompatibility, and clinical efficacy studies are needed to confirm the in vivo anti-Candida activity of these novel resins
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