3,300 research outputs found

    Dynamics of Overhauser Field under nuclear spin diffusion in a quantum dot

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    The coherence of electron spin can be significantly enhanced by locking the Overhauser field from nuclear spins using the nuclear spin preparation. We propose a theoretical model to calculate the long time dynamics of the Overhauser field under intrinsic nuclear spin diffusion in a quantum dot. We obtain a simplified diffusion equation that can be numerically solved and show quantitatively how the Knight shift and the electron-mediated nuclear spin flip-flop affect the nuclear spin diffusion. The results explain several recent experimental observations, where the decay time of Overhauser field is measured under different configurations, including variation of the external magnetic field, the electron spin configuration in a double dot, and the initial nuclear spin polarization rate.Comment: 6 pages, 5 figure

    Cytosorb® haemoadsorption: a potential game changer for patients needing myocardial surgical revascularisation

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    Cytosorb, an extracorporeal blood purification system, utilises the principles of haemoadsorption to remove low molecular weight substances from the blood, including multiple cytokines such as interleukin (IL)-1b, IL-6, IL-8, and tumour necrosis factor-α, and anti-platelet drugs aiming to improve clinical outcomes. Given the prominent role of pro-inflammatory cytokines in various inflammatory states, Cytosorb has seen growing application as a therapeutic immunomodulator including surgery. This review focuses on the effects of the use of Cytosorb in patients undergoing coronary artery bypass grafting (CABG) and the indications of removal of cytokines and anti-platelet agents such as ticagrelor. The evidence supports the feasibility and safety profile of Cytosorb, with no device-related adverse events reported in all studies. Initial studies suggest significant potential for Cytosorb in urgent or emergency CABG surgery to remove anti-platelet medication with promising benefits on clinical outcomes including fewer blood product transfusions, decreased length of intensive care unit stay, and lower re-sternotomy rates. Furthermore, a cost saving analysis indicated that intraoperative removal of ticagrelor with Cytosorb would be cost effective in the setting of emergency cardiac surgery. However, the evidence remains inconclusive when Cytosorb is used in elective CABG surgery for cytokine removal. Definite high quality clinical trials for both indications for Cytosorb in CABG surgery are needed to clarify if there is a clinically significant benefit in clinical outcomes. There is substantial trial activity for the application of Cytosorb in higher risk cardiac surgery to establish the place of Cytosorb in future treatment pathways in cardiac surgery

    Gonadotropins for pubertal induction in males with hypogonadotropic hypogonadism: systematic review and meta-analysis.

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    OBJECTIVE: Hypogonadotropic hypogonadism is characterized by inadequate secretion of pituitary gonadotropins, leading to absent, partial, or arrested puberty. In males, classical treatment with testosterone promotes virilization but not testicular growth or spermatogenesis. To quantify treatment practices and efficacy, we systematically reviewed all studies investigating gonadotropins for the achievement of pubertal outcomes in males with hypogonadotropic hypogonadism. DESIGN: Systematic review and meta-analysis. METHODS: A systematic review of Medline, Embase, Global Health, and PsycINFO databases in December 2022. Risk of Bias 2.0/Risk Of Bias In Non-randomized Studies of Interventions/National Heart, Lung, and Blood Institute tools for quality appraisal. Protocol registered on PROSPERO (CRD42022381713). RESULTS: After screening 3925 abstracts, 103 studies were identified including 5328 patients from 21 countries. The average age of participants was <25 years in 45.6% (n = 47) of studies. Studies utilized human chorionic gonadotropin (hCG) (n = 93, 90.3% of studies), human menopausal gonadotropin (n = 42, 40.8%), follicle-stimulating hormone (FSH) (n = 37, 35.9%), and gonadotropin-releasing hormone (28.2% n = 29). The median reported duration of treatment/follow-up was 18 months (interquartile range 10.5-24 months). Gonadotropins induced significant increases in testicular volume, penile size, and testosterone in over 98% of analyses. Spermatogenesis rates were higher with hCG + FSH (86%, 95% confidence interval [CI] 82%-91%) as compared with hCG alone (40%, 95% CI 25%-56%). However, study heterogeneity and treatment variability were high. CONCLUSIONS: This systematic review provides convincing evidence of the efficacy of gonadotropins for pubertal induction. However, there remains substantial heterogeneity in treatment choice, dose, duration, and outcomes assessed. Formal guidelines and randomized studies are needed

    State/Operator Correspondence in Higher-Spin dS/CFT

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    A recently conjectured microscopic realization of the dS4_4/CFT3_3 correspondence relating Vasiliev's higher-spin gravity on dS4_4 to a Euclidean Sp(N)Sp(N) CFT3_3 is used to illuminate some previously inaccessible aspects of the dS/CFT dictionary. In particular it is argued that states of the boundary CFT3_3 on S2S^2 are holographically dual to bulk states on geodesically complete, spacelike R3R^3 slices which terminate on an S2S^2 at future infinity. The dictionary is described in detail for the case of free scalar excitations. The ground states of the free or critical Sp(N)Sp(N) model are dual to dS-invariant plane-wave type vacua, while the bulk Euclidean vacuum is dual to a certain mixed state in the CFT3_3. CFT3_3 states created by operator insertions are found to be dual to (anti) quasinormal modes in the bulk. A norm is defined on the R3R^3 bulk Hilbert space and shown for the scalar case to be equivalent to both the Zamolodchikov and pseudounitary C-norm of the Sp(N)Sp(N) CFT3_3.Comment: 24 page

    Permeating the social justice ideals of equality and equity within the context of Early Years: challenges for leadership in multi-cultural and mono-cultural primary schools

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    The ideology and commitment of social justice principles is central to Early Years practice, however, the term social justice in education is complex and remains contested. This paper explores the ideology of social justice through links between equality and equity and how it is embedded within Early Years, and what remain the potential challenges for leadership. Interviews in English multi-cultural and mono-cultural primary schools were conducted. Findings showed that the ideology of social justice, equality and equity was interpreted differently. Multi-cultural schools appear to use a greater variety of activities to embed social justice principles that involved their diverse communities more to enrich the curriculum. In mono-cultural schools leadership had to be more creative in promoting equality and equity given the smaller proportion of their diverse pupil and staff population. Tentative conclusions suggest that the vision for permeating equality and equity in Early Years, at best, is at early stages

    Anisotropic colloids through non-trivial buckling

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    We present a study on buckling of colloidal particles, including experimental, theoretical and numerical developments. Oil-filled thin shells prepared by emulsion templating show buckling in mixtures of water and ethanol, due to dissolution of the core in the external medium. This leads to conformations with a single depression, either axisymmetric or polygonal depending on the geometrical features of the shells. These conformations could be theoretically and/or numerically reproduced in a model of homogeneous spherical thin shells with bending and stretching elasticity, submitted to an isotropic external pressure.Comment: submitted to EPJ

    GaP-ZnS Multilayer Films:Visible-Light Photoelectrodes by Interface Engineering

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    In the field of solar water splitting, searching for and modifying bulk compositions have been the conventional approaches to enhancing visible-light activity. In this work, manipulation of heterointerfaces in ZnS-GaP multilayer films is demonstrated as a successful alternative approach to achieving visible-light-active photoelectrodes. The photocurrent measured under visible light increases with the increasing number of interfaces for ZnS-GaP multilayer films with the same total thickness, indicating it to be a predominantly interface-driven effect. The activity extends to long wavelengths (650 nm), much longer than those expected for pure ZnS and also longer than those previously reported for GaP. Density functional theory calculations of ZnS-GaP multilayers predict the presence of electronic states associated with atoms at the interfaces between ZnS and GaP that are different from those found within the layers away from the interfaces; these states, formed due to unique bonding environments found at the interfaces, lead to a lowering of the band gap and hence the observed visible-light activity. The presence of these electronic states attributed to the interfaces is confirmed by depth-resolved X-ray photoelectron spectroscopy. Thus, we show that interface engineering is a promising route for overcoming common deficiencies of individual bulk materials caused by both wide band gaps and indirect band gaps and hence enhancing visible-light absorption and photoelectrochemical performance

    The Higher Spin/Vector Model Duality

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    This paper is mainly a review of the dualities between Vasiliev's higher spin gauge theories in AdS4 and three dimensional large N vector models, with focus on the holographic calculation of correlation functions of higher spin currents. We also present some new results in the computation of parity odd structures in the three point functions in parity violating Vasiliev theories.Comment: 55 pages, 1 figure. Contribution to J. Phys. A special volume on "Higher Spin Theories and AdS/CFT" edited by M. R. Gaberdiel and M. Vasiliev. v2: references adde
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