1,236 research outputs found
Hypersonic modes in nanophononic semiconductors
Frequency gaps and negative group velocities of hypersonic phonon modes in periodically arranged composite semiconductors are presented. Trends and criteria for phononic gaps are discussed using a variety of atomic-level theoretical approaches. From our calculations, the possibility of achieving semiconductor-based one-dimensional phononic structures is established. We present results of the location and size of gaps, as well as negative group velocities of phonon modes in such structures. In addition to reproducing the results of recent measurements of the locations of the band gaps in the nanosized Si/Si0.4Ge0.6 superlattice, we show that such a system is a true one-dimensional hypersonic phononic crystal
Problematic plate reconstruction
Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Geoscience 5 (2012): 676-677, doi:10.1038/ngeo1596.As has been previously proposed, Bronner et al. suggest that opening
of the rift between Newfoundland and Iberia involved exhumation of mantle rocks until
112 million years ago, subsequent seafloor spreading, and crustal thickening along the
high-amplitude J magnetic anomaly by magma that propagated from the Southeast
Newfoundland Ridge area. Conventionally, the anomalous magnetism and basement
ridges associated with the J anomaly north of the Newfoundland-Gibraltar Fracture Zone
are thought to have formed about 125 million years ago at chron M0 (Fig. 1a), although
the crust probably experienced some later magmatic overprinting. The M0 age would
make their formation simultaneous with that of the similar J anomaly and basement
ridges (the J Anomaly Ridge and Madeira Tore Rise) along the Mid-Atlantic Ridge to the
south and place them within a zone of exhumed mantle in the Newfoundland-Iberia
rift. In contrast, Bronner et al. propose that the J anomaly and associated basement
ridges were formed by later magmatism (about 112 million years ago) that marked the
end of mantle exhumation in the rift. We argue here that constraints from plate tectonic
reconstructions render this possibility untenable.2013-04-0
Hypolipidemic, Hypoglycemic and Anti-oxidant Activities of Flower Extracts of Allamanda Violacea A. DC (Apocynaceae)
Purpose: To investigate the anti-dyslipidemic, anti-oxidant and anti-diabetic activities of the aqueous extract and solvent fractions of A. violacea flowers.Methods: The aqueous extract was fractionated into petroleum ether, ether, chloroform, chloroformmethanol (4:1) and chloroform-methanol (3:2) fractions. Lipid lowering activity was evaluated in two models, viz, triton WR-1339 - induced hyperlipimea in rats as well as fructose-rich high fat diet. To assess anti-oxidant activity, in-vitro model of non-enzymic superoxide hydroxyl radicals and microsomal lipid peroxidation by non-enzymic inducer was adopted. Hypoglycemic activity was evaluated by sucrose-loaded rat model.Results: Amongst the fractions, ether and chloroform fractions caused marked decrease in the levels of total cholesterol (Tc), triglycerides (Tg), plasma lipids (Pl), and protein by 24, 23, 23 and 22 %, and 24, 22, 23 and 19 %, respectively. In rats fed with high fat diet (HFD), ether and chloroform fractions lowered Tc, Tg and, Pl by 26, 25 and 26 %, and 18, 19 and 20 %, respectively. Significant decrease in superoxide anions, hydroxyl radicals and microsomal lipid peroxidation by ether and chloroform fractions was also observed. Chloroform, chloroform-methanol (4:1) and chloroform-methanol (3:2) fractions showed antihyperglycaemic activity to the extent of 25.2, 21.6 and 23.2 %, respectively.Conclusion: The flowers of this plant, especially the ether and chloroform extracts, may be suitable as an anti-oxidant supplement for lipid management.Keywords: Allamanda violacea flowers, Anti-hyperlipidemic,  Anti-hyperglycemic, Anti-oxidant
Double coin in esophagus at same location and same alignment - a rare occurrence: a case report
Coin is the most common foreign body swallowed by pediatric age group. The multiple coin swallowing is extremely rare and very few cases had been reported in English literature. Most of them were present at different site and had different alignment in the esophagus. The location of the coin (trachea vs. esophagus) is commonly determined by the alignment of the coin on radiographic studies. A 4-year-girl was presented to us with history of coin ingestions one day back without any respiratory distress. On radiological study there was suspicion of two coins on same location and alignment. The diagnosis was confirmed after removal. The both coin was removed successfully by esophagoscopy. Unexpected second foreign bodies in pediatric esophageal coin ingestions are rare and it is mandatory to do post operative radiography after removal to exclude duplex coin or tracheal coin. We are presenting this case because of its rarity, difficulty in diagnosis especially when proper history is not available
Single-Stage Repair versus Traditional Repair of High Anorectal Malformations, Functional Results’ Correlation with Kelly’s Score and Postoperative Magnetic Resonance Imaging Findings
Introduction: Posterior sagittal anorectoplasty (PSARP) is the standard treatment for anorectal malformations. In the present study, the clinical evaluation of anal continence was carried out using Kelly’s scoring system and the results of primary PSARP or abdomino-PSARP were compared with the traditional three-stage procedure and the functional outcome was correlated with the findings of MRI, which was used as an objective method of evaluation.Patients and methods: A total of 40 patients with intermediate and high anorectal malformations were studied and were divided into two groups on the basis of a random number table. The patients in group A were treated with a single-stage operation, whereas the patients in group B were treated with a standard staged operation (either PSARP or abdominoperineal pull-through). After clinical evaluation using the Kelly score, patients were divided into three clinical groups irrespective of whether they were operated in one stage or in three stages. All patients were subjected to MRI at the age of 3 years and the findings were correlated with the clinical scoring system.Result: Patients were categorized according to their Kelly’s scores as follows: group 1: clinically good (score 5–6); group 2: clinically fair (score 3–4); and group 3: clinically poor (score 0–2). The proportions of good development of the muscles (puborectalis, external sphincter muscle, and levator muscle hammock) were 78.9% in group 1, 40% in group 2, and none in group 3. Development of muscles was found to be a significant factor for anal continence. Other significant factors for anal continence are rectal diameter and anorectal angle.Conclusion: Clinical assessment using the Kelly score was similar for the single-stage operation and the staged procedure, and this was supported by MRI findings. Therefore, we recommend the single-stage procedure to achieve a better outcome in intermediate and high anorectal malformation.Keywords: Anorectal Malformations, MRI, Posterior Sagittal Anorectoplast
Effect of arsenic-phosphorus interaction on arsenic-induced oxidative stress in chickpea plants
Arsenic-induced oxidative stress in chickpea was investigated under glasshouse conditions in response to application of arsenic and phosphorus. Three levels of arsenic (0, 30 and 60 mg kg−1) and four levels of P (50, 100, 200, and 400 mg kg−1) were applied to soil-grown plants. Increasing levels of both arsenic and P significantly increased arsenic concentrations in the plants. Shoot growth was reduced with increased arsenic supply regardless of applied P levels. Applied arsenic induced oxidative stress in the plants, and the concentrations of H2O2 and lipid peroxidation were increased. Activity of superoxide dismutase (SOD) and concentrations of non-enzymatic antioxidants decreased in these plants, but activities of catalase (CAT) and ascorbate peroxidase (APX) were significantly increased under arsenic phytotoxicity. Increased supply of P decreased activities of CAT and APX, and decreased concentrations of non-enzymatic antioxidants, but the high-P plants had lowered lipid peroxidation. It can be concluded that P increased uptake of arsenic from the soil, probably by making it more available, but although plant growth was inhibited by arsenic the P may have partially protected the membranes from arsenic-induced oxidative stress
A human MAP kinase interactome.
Mitogen-activated protein kinase (MAPK) pathways form the backbone of signal transduction in the mammalian cell. Here we applied a systematic experimental and computational approach to map 2,269 interactions between human MAPK-related proteins and other cellular machinery and to assemble these data into functional modules. Multiple lines of evidence including conservation with yeast supported a core network of 641 interactions. Using small interfering RNA knockdowns, we observed that approximately one-third of MAPK-interacting proteins modulated MAPK-mediated signaling. We uncovered the Na-H exchanger NHE1 as a potential MAPK scaffold, found links between HSP90 chaperones and MAPK pathways and identified MUC12 as the human analog to the yeast signaling mucin Msb2. This study makes available a large resource of MAPK interactions and clone libraries, and it illustrates a methodology for probing signaling networks based on functional refinement of experimentally derived protein-interaction maps
Stochastic Blockmodeling for the Analysis of Big Data
The aim of this paper is to consider the stochastic blockmodel to obtain clusters of units as regards patterns of similar relations; moreover we want to analyze the relations between clusters. Blockmodeling is a technique usually applied in social network analysis focusing on the relations between \u201cactors\u201d i.e. units. In our time people and devices constantly generate data. The network is generating location and other data that keeps services running and ready to use in every moment. This rapid development in the availability and access to data has induced the need for better analysis techniques to understand the various phenomena. Blockmodeling techniques and Clustering algorithms, can be used for this aim. In this paper application regards the Web
Annual variation in the levels of transcripts of sex-specific genes in the mantle of the common mussel, Mytilus edulis
Mytilus species are used as sentinels for the assessment of environmental health but sex or stage in the reproduction cycle is rarely considered even though both parameters are likely to influence responses to pollution. We have validated the use of a qPCR assay for sex identification and related the levels of transcripts to the reproductive cycle. A temporal study of mantle of Mytilus edulis found transcripts of male-specific vitelline coat lysin (VCL) and female-specific vitelline envelope receptor for lysin (VERL) could identify sex over a complete year. The levels of VCL/VERL were proportional to the numbers of sperm/ova and are indicative of the stage of the reproductive cycle. Maximal levels of VCL and VERL were found in February 2009 declining to minima between July - August before increasing and re-attaining a peak in February 2010. Water temperature may influence these transitions since they coincide with minimal water temperature in February and maximal temperature in August. An identical pattern of variation was found for a cryptic female-specific transcript (H5) but a very different pattern was observed for oestrogen receptor 2 (ER2). ER2 varied in a sex-specific way with male > female for most of the cycle, with a female maxima in July and a male maxima in December. Using artificially spawned animals, the transcripts for VCL, VERL and H5 were shown to be present in gametes and thus their disappearance from mantle is indicative of spawning. VCL and VERL are present at equivalent levels in February and July-August but during gametogenesis (August to January) and spawning (March to June) VCL is present at lower relative amounts than VERL. This may indicate sex-specific control mechanisms for these processes and highlight a potential pressure point leading to reduced reproductive output if environmental factors cause asynchrony to gamete maturation or release
Unusual acquired gastric outlet obstruction during infancy: a case report
Acquired gastric outlet obstruction (GOO) during infancy beyond the neonatal period is a very rare condition when other congenital causes like infantile hypertrophic pyloric stenosis, antral diaphragm, pyloric atresia etc are excluded. We report an unusual case of 6 month old male child who presented with recurrent episode of vomiting not relieved by medication. On gastrograffin study there was pre pyloric stricture of unknown etiology and was managed by stricturoplasty. We are reporting this case because of its rarity and with excellent outcome if diagnosed and managed properly. Even on extensive search of English literature we are not able to find a single report of this lesion in infants
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