3,496 research outputs found
Analytical solutions of the Klein-Fock-Gordon equation with the Manning-Rosen potential plus a Ring-Shaped like potential
In this work, on the condition that scalar potential is equal to vector
potential, the bound state solutions of the Klein-Fock-Gordon equation of the
Manning-Rosen plus ring-shaped like potential are obtained by Nikiforov-Uvarov
method. The energy levels are worked out and the corresponding normalized
eigenfunctions are obtained in terms of orthogonal polynomials for arbitrary
states. The conclusion also contain central Manning-Rosen, central and
non-central Hulth\'en potential.Comment: 14 pages. arXiv admin note: substantial text overlap with
arXiv:1210.537
The effect of melatonin on bacterial translocation following ischemia/reperfusion injury in a rat model of superior mesenteric artery occlusion
Background: Acute mesenteric ischemia is a life-threatening vascular emergency resulting in tissue destruction due to ischemia-reperfusion injury. Melatonin, the primary hormone of the pineal gland, is a powerful scavenger of reactive oxygen species (ROS), including the hydroxyl and peroxyl radicals, as well as singlet oxygen, and nitric oxide. In this study, we aimed to investigate whether melatonin prevents harmful effects of superior mesenteric ischemia-reperfusion on intestinal tissues in rats. Methods: Rats were randomly divided into three groups, each having 10 animals. In group I, the superior mesenteric artery (SMA) was isolated but not occluded. In group II and group III, the SMA was occluded immediately distal to the aorta for 60 minutes. After that, the clamp was removed and the reperfusion period began. In group III, 30 minutes before the start of reperfusion, 10 mg/kg melatonin was administered intraperitonally. All animals were sacrified 24 hours after reperfusion. Tissue samples were collected to evaluate the I/R-induced intestinal injury and bacterial translocation (BT). Results: There was a statistically significant increase in myeloperoxidase activity, malondialdehyde levels and in the incidence of bacterial translocation in group II, along with a decrease in glutathione levels. These investigated parameters were found to be normalized in melatonin treated animals (group III). Conclusion: We conclude that melatonin prevents bacterial translocation while precluding the harmful effects of ischemia/reperfusion injury on intestinal tissues in a rat model of superior mesenteric artery occlusion. © 2015 Ozban et al.; licensee BioMed Central
Role of Alpha Oscillations During Short Time Memory Task Investigated by Graph Based Partitioning
In this study, we investigate the clustering pattern of alpha band (8 Hz - 12 Hz) electroencephalogram (EEG) oscillations obtained from healthy individuals during a short time memory task with 3 different memory loads. The retention period during which subjects were asked to memorize a pattern in a square matrix is analyzed with a graph theoretical approach. The functional coupling among EEG electrodes are quantified via mutual information in the time-frequency plane. A spectral clustering algorithm followed by bootstrapping is used to parcellate memory related circuits and for identifying significant clusters in the brain. The main outcome of the study is that the size of the significant clusters formed by alpha oscillations decreases as the memory load increases. This finding corroborates the active inhibition hypothesis about alpha oscillations
Stable propagation of an ordered array of cracks during directional drying
We study the appearance and evolution of an array of parallel cracks in a
thin slab of material that is directionally dried, and show that the cracks
penetrate the material uniformly if the drying front is sufficiently sharp. We
also show that cracks have a tendency to become evenly spaced during the
penetration. The typical distance between cracks is mainly governed by the
typical distance of the pattern at the surface, and it is not modified during
the penetration. Our results agree with recent experimental work, and can be
extended to three dimensions to describe the properties of columnar polygonal
patterns observed in some geological formations.Comment: 8 pages, 4 figures, to appear in PR
Permeability evolution during progressive development of deformation bands in porous sandstones
[1] Triaxial deformation experiments were carried out on large (0.1 m) diameter cores of a porous sandstone in order to investigate the evolution of bulk sample permeability as a function of axial strain and effective confining pressure. The log permeability of each sample evolved via three stages: (1) a linear decrease prior to sample failure associated with poroelastic compaction, (2) a transient increase associated with dynamic stress drop, and (3) a systematic quasi-static decrease associated with progressive formation of new deformation bands with increasing inelastic axial strain. A quantitative model for permeability evolution with increasing inelastic axial strain is used to analyze the permeability data in the postfailure stage. The model explicitly accounts for the observed fault zone geometry, allowing the permeability of individual deformation bands to be estimated from measured bulk parameters. In a test of the model for Clashach sandstone, the parameters vary systematically with confining pressure and define a simple constitutive rule for bulk permeability of the sample as a function of inelastic axial strain and effective confining pressure. The parameters may thus be useful in predicting fault permeability and sealing potential as a function of burial depth and faul
Proximate Analysis of Seed Extracts and Methanol Content of Juice of Some Grape Varieties in Turkey
The present study describes the determination and comparison of antibacterial activity, total phenolic content in seeds of seven popular grape cultivars and methanol content of grape juice grown in Turkey. It's called Muskule, Gokuzum, Razaki, Akuzum, Eksi kara, Siyah pekmezlik and Buzgulu in Turkey. The antibacterial activity was evaluated by the microdilution method and the minimum inhibition concentrations of extracts from determined. The phenolic content was determined using spectrophotometer. Pollution from methyl alcohol, which is extremely harmful for human health was determined using GC. The minimum inhibitory concentration (MIC) values of grape extracts with antibacterial activity ranged from 0,312 to 5 µg/ml. The total phenolic content of grape seed of Ekşi kara was found to be about one-half times as mg GAE/g compare to Büzgülü. The highest methyl alcohol ratios are found in Ekşi kara among juice of grape varieties (12.01 g/µl)
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