925 research outputs found

    Conductance, Valley and Spin polarization and Tunnelling magneto-resistance in ferromagnetic-normal-ferromagnetic junctions of silicene

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    We investigate charge conductance and spin and valley polarization along with the tunnelling magneto-resistance (TMR) in silicene junctions composed of normal silicene and ferromagnetic silicene. We show distinct features of the conductances for parallel and anti-parallel spin configurations and the TMR, as the ferromagnetic-normal-ferromagnetic (FNF) junction is tuned by an external electric field. We analyse the behavior of the charge conductance and valley and spin polarizations in terms of the independent conductances of the different spins at the two valleys and the band structure of ferromagnetic silicene and show how the conductances are affected by the vanishing of the propagating states at one or the other valley. In particular, unlike in graphene, the band structure at the two valleys are independently affected by the spin in the ferromagnetic regions and lead to non-zero, and in certain parameter regimes, pure valley and spin polarizations, which can be tuned by the external electric field. We also investigate the oscillatory behavior of the TMR with respect to the strength of the barrier potential (both spin-independent and spin-dependent barriers) in the normal silicene region and note that in some parameter regimes, the TMR can even go from positive to negative values, as a function of the external electric field.Comment: This is the published versio

    Role of SHP2 in hematopoiesis and leukemogenesis

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    Purpose of review SH2 domain-containing tyrosine phosphatase 2 (SHP2), encoded by PTPN11 plays an important role in regulating signaling from cell surface receptor tyrosine kinases during normal development as well as oncogenesis. Herein we review recently discovered roles of SHP2 in normal and aberrant hematopoiesis along with novel strategies to target it. Recent findings Cell autonomous role of SHP2 in normal hematopoiesis and leukemogenesis has long been recognized. The review will discuss the newly discovered role of SHP2 in lineage specific differentiation. Recently, a noncell autonomous role of oncogenic SHP2 has been reported in which activated SHP2 was shown to alter the bone marrow microenvironment resulting in transformation of donor derived normal hematopoietic cells and development of myeloid malignancy. From being considered as an ‚Äėundruggable‚Äô target, recent development of allosteric inhibitor has made it possible to specifically target SHP2 in receptor tyrosine kinase driven malignancies. Summary SHP2 has emerged as an attractive target for therapeutic targeting in hematological malignancies for its cell autonomous and microenvironmental effects. However a better understanding of the role of SHP2 in different hematopoietic lineages and its crosstalk with signaling pathways activated by other genetic lesions is required before the promise is realized in the clinic

    Fetal foot length for assessment of gestational age: a cross sectional study

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    Background: Fetal age actually begins at conception and an equivalent term is conceptional age. Uncertain gestational age (GA) has been associated with adverse pregnancy outcomes independent of maternal characteristics. The objective was to evaluate the accuracy of fetal foot length (FFL) in estimation of gestational age.Methods: It was a cross sectional study. Trans abdominal ultrasound on 150 pregnant women with normal singleton pregnancies between 16 to 40 weeks was done to measure FFL. The relationship between GA and FFL was analysed by simple linear regression.Results: A linear relationship was demonstrated between FFL and GA. (GA (in weeks)=7.490+0.393√óFFL (in mm)) with significant correlation (r=0.985, p<0.001).Conclusions: Ultrasonographic measurement of FFL is a reliable indicator of gestational age and can be a useful alternative to estimate GA when other routine biometric parameters are not conclusive

    The Artisan Lens: Effects on Vision Quality, the Corneal Endothelium and Vision-Related Quality of Life

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    Refractive errors are the most frequent disorders of the eye. In the ideal refractive state, emmetropia, an image is focused directly on the retina, resulting in the perception of a sharp image in a healthy visual system. Such eyes do not require glasses or contact lenses to see sharply. Most eyes, however, have some degree of refractive error, although correction is not always required. In myopia (nearsightedness), the image appears focused anterior to the retina, producing a sharp image at near and a blurred image at distance. A concave lens (minus Diopter) is required to sharpen the image. The reverse is true in hypermetropia (also known as hyperopia or farsightedness), where the image is projected posterior to the retina, producing a blurred image at near and a sharper image at distance. A convex lens (plus Diopter) is required to produce a clear image. Astigmatism (cylindrical error) is the result of two different refractive powers between two perpendicular meridians. A cylindrical correction can correct this problem. Extreme cases of all these refractive errors can cause severe visual loss. Anisometropia is the presence of two significantly different refractive errors. In these situations, simple spectacle correction is not always suitable due to aniseikonia (different sized images) resulting from the different powers in the lenses; other options such as

    Investigation of anti-inflammatory activity of ethanolic extract of Aconitum Napellus Linn against carrageenan induced paw edema in rats

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    The Indian herbal medicine is evaluated by comprehensive activity of research on herbal plant species and their therapeutic principles in the whole world. In traditional and modern medicine, the medicinal plants are used which have shown their potential in possessing potent bioactive compound. A large number of populations suffer due to various reasons from rheumatoid arthritis of unknown inflammation. The present work is to investigation of anti-inflammatory activity of herbal extracts of Aconitum Napellus Linn against carrageenan induced paw edema in rats. Aconitum Napellus Linn plant extracts used in traditional medicine was investigated for their anti-inflammatory potential against adjuvant carrageenan induced inflammation. Maceration method was used for preparing ethanolic extract. In adjuvant carrageenan induced inflammation, orally administered extracts (100 mg/kg), inhibited the acute as well as chronic inflammation. The ethanolic herbal extract of plant under investigation showed potent anti-inflammatory activity. The anti-inflammatory activity of the extracts was compared to reference drug, diclofenac (10 mg/kg). Keywords: Anti-inflammatory, Paw edema, Aconitum napelluslinn, Maceration

    Electronic confinement of surface states in a topological insulator nanowire

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    We analyze the confinement of electronic surface states in a model of a topological insulator nanowire. Spin-momentum locking in the surface states reduces unwanted backscattering in the presence of non-magnetic disorder and is known to counteract localization for certain values of magnetic flux threading the wire. We show that intentional backscattering can be induced for a range of conditions in the presence of a nanowire constriction. We propose a geometry for a nanowire that involves two constrictions and show that these regions form effective barriers that allow for the formation of a quantum dot. We analyze the zero-temperature non-interacting electronic transport through the device using the Landauer-B\"{u}ttiker approach and show how externally applied magnetic flux parallel to the nanowire and electrostatic gates can be used to control the spectrum of the quantum dot and the electronic transport through the surface states of the model device

    Maternal risk factors associated with term low birth weight in India: A review

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    Low birth weight is one of the leading factors for infant morbidity and mortality. To a large extent affect, various maternal risk factors are associated with pregnancy outcomes by increasing odds of delivering an infant with low birth weight. Despite this association, understanding the maternal risk factors affecting term low birth weight has been a challenging task. To date, limited studies have been conducted in India that exert independent magnitude of these effects on term low birth weight. The aim of this review is to examine the current knowledge of maternal risk factors that contribute to term low birth weight in the Indian population. In order to identify the potentially relevant articles, an extensive literature search was conducted using PubMed, Goggle Scholar and IndMed databases (1993 ‚Äď Dec 2020). Our results indicate that maternal age, educational status, socio-economic status, ethnicity, parity, pre-pregnancy weight, maternal stature, maternal body mass index, obstetric history, maternal anaemia, gestational weight gain, short pregnancy outcome, hypertension during pregnancy, infection, antepartum haemorrhage, tobacco consumption, maternal occupation, maternal psychological stress, alcohol consumption, antenatal care and mid-upper arm circumference have all independent effects on term low birth weight in the Indian population. Further, we argue that exploration for various other dimensions of maternal factors and underlying pathways can be useful for a better understanding of how it exerts independent association on term low birth weight in the Indian sub-continent

    First Results of the 140^{140}Ce(n,ő≥)141^{141}Ce Cross-Section Measurement at n_TOF

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    An accurate measurement of the 140^{140}Ce(n,ő≥) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the 140^{140}Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in 140^{140}Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the 140^{140}Ce Maxwellian-averaged cross-section

    First Results of the 140^{140}Ce(n,ő≥)141^{141}Ce Cross-Section Measurement at n_TOF

    Get PDF
    An accurate measurement of the 140^{140}Ce(n,ő≥) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the 140^{140}Ce capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in 140^{140}Ce to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the 140^{140}Ce Maxwellian-averaged cross-section
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