1,907 research outputs found
A Shock Wave Attached to a Pointed Obstacle in a Steady flow of a Dissociating Gas
A pointed obstacle is assumed symmetrically placed with respect to a uniform supersonic flow ahead of it. It is assumed that an oblique shock wave attached to the leading edge of the obstacle appears form the vertex so that the flow after the shock is along the surface of the obstacle. In this paper a relation between the curvature of an attached shock wave and that of a stream line is discovered. It is concluded that in a steady flow of an ideal dissociating gas, the stream lines at the rear of a straight attached shock wave are necessarily curved lines, whereas in an ordinary gas flow only a straight line flow is possible behind a straight shock
Electronic screening and damping in magnetars
We calculate the screening of the ion-ion potential due to electrons in the
presence of a large background magnetic field, at densities of relevance to
neutron star crusts. Using the standard approach to incorporate electron
screening through the one-loop polarization function, we show that the magnetic
field produces important corrections both at short and long distances. In
extreme fields, realized in highly magnetized neutron stars called magnetars,
electrons occupy only the lowest Landau levels in the relatively low density
region of the crust. Here our results show that the screening length for
Coulomb interactions between ions can be smaller than the inter-ion spacing.
More interestingly, we find that the screening is anisotropic and the screened
potential between two static charges exhibits long range Friedel oscillations
parallel to the magnetic field. This long-range oscillatory behavior is likely
to affect the lattice structure of ions, and can possibly create rod-like
structures in the magnetar crusts. We also calculate the imaginary part of the
electron polarization function which determines the spectrum of electron-hole
excitations and plays a role in damping lattice phonon excitations. We
demonstrate that even for modest magnetic fields this damping is highly
anisotropic and will likely lead to anisotropic phonon heat transport in the
outer neutron star crust.Comment: 14 pages, 5 Figure
OCT based evaluation of retinal changes in multiple sclerosis
Background: Optical coherence tomography is a non-invasive imaging technique routinely used in ophthalmology to visualize and quantify the layers of the retina. It also provides information on optic nerve head topography, peripapillary retinal nerve fibre layer thickness and macular volume which correlate with axonal loss. These measurements are of interest in optic neuropathies and in multiple sclerosis. The OCT parameters are now used as endpoints in neurologic clinical trials.Methods: A prospective study involving 30 patients of multiple sclerosis and equal number of age and sex matched controls were subjected to evaluation of retinal changes (peripapillary retinal nerve fiber layer and central macular thickness) using Zeiss Cirrus HD-OCT machine. The results collected were then subjected to statistical analysis.Results: Significant RNFL thinning was seen in patients of multiple sclerosis compared to the age and sex matched controls. Marked thinning was seen in superior and temporal quadrants of right eye (p value of 0.002 and 0.008 respectively) and all quadrants in left eye with a p value of < 0.001. Patients with multiple sclerosis for more than 5 yrs showed statistically significant RNFL thinning in the superior quadrant of right eye (p<.005), however, no such changes were seen in rest of the quadrants of right eye and in none of the quadrants of left eye Significant RNFL thinning was seen in the patients of multiple sclerosis without prior history of optic neuritis than patients with prior history of optic neuritis which was statistically significant with p value of .001.Conclusions: Patients with multiple sclerosis for more than 5 yrs showed statistically significant RNFL thinning in the superior quadrant of right eye (p<.005). Significant RNFL thinning was seen in the patients of multiple sclerosis without prior history of optic neuritis than patients with prior history of Optic neuritis which was statistically significant with p value of .001. No significant changes were seen in central macular thickness in multiple sclerosis compared to the controls which was corroborated by statistical analysis (p value of 0.37)
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Non-coding and Coding Transcriptional Profiles Are Significantly Altered in Pediatric Retinoblastoma Tumors.
Retinoblastoma is a rare pediatric tumor of the retina, caused by the homozygous loss of the Retinoblastoma 1 (RB1) tumor suppressor gene. Previous microarray studies have identified changes in the expression profiles of coding genes; however, our understanding of how non-coding genes change in this tumor is absent. This is an important area of research, as in many adult malignancies, non-coding genes including LNC-RNAs are used as biomarkers to predict outcome and/or relapse. To establish a complete and in-depth RNA profile, of both coding and non-coding genes, in Retinoblastoma tumors, we conducted RNA-seq from a cohort of tumors and normal retina controls. This analysis identified widespread transcriptional changes in the levels of both coding and non-coding genes. Unexpectedly, we also found rare RNA fusion products resulting from genomic alterations, specific to Retinoblastoma tumor samples. We then determined whether these gene expression changes, of both coding and non-coding genes, were also found in a completely independent Retinoblastoma cohort. Using our dataset, we then profiled the potential effects of deregulated LNC-RNAs on the expression of neighboring genes, the entire genome, and on mRNAs that contain a putative area of homology. This analysis showed that most deregulated LNC-RNAs do not act locally to change the transcriptional environment, but potentially function to modulate genes at distant sites. From this analysis, we selected a strongly down-regulated LNC-RNA in Retinoblastoma, DRAIC, and found that restoring DRAIC RNA levels significantly slowed the growth of the Y79 Retinoblastoma cell line. Collectively, our work has generated the first non-coding RNA profile of Retinoblastoma tumors and has found that these tumors show widespread transcriptional deregulation
Phase evolution during Conventional and Flash Sintering of hydroxyapatite-zirconia composite using in-situ synchrotron x-ray diffraction
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Carica Papaya’s Anti-Diabetic and Anti-Cancer Properties – A Review
The Carica papaya originates from the Caricaceae family, and various members of this family have been used as treatments for a range of ailments. The perennial plant C. papaya, which is currently found over the whole tropical region, is thought to have originated in the southern region of Mexico. To assess the biological activity of distinct C. papaya sections, several scientific studies have been carried out. Since ancient times, the papaya plant's many components have been employed for medicinal purposes. In this article, the process of extracting Carica papaya leaves as well as the anti-cancer and anti-diabetic properties of papaya leaf activity were all things we wanted to assess. The information for this review paper, which focuses mostly on the therapeutic potential of papaya leaf extract was obtained via researching a collection of wider internet databases, including Google Scholar, PubMed, Science Direct, and Elsevier. The papaya plant, which has different parts such as fruit, leaves, seeds, bark, latex, and other substances, is very important in controlling the spread of illness. Alkaloids, glycosides, tannins, saponins, and flavonoids are just a few of the bioactive constituents in this, we focused on the papaya plant leaf's anti-cancer and anti-diabetic properties. The papaya has a wide range of therapeutic qualities. Papaya is a potent remedy, according to traditional beliefs. Biological activities have been the subject of much research. In the current review, all the pharmacological applications and activities of certain chemical components are discussed
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