Transient electric current through an Aharonov-Bohm ring after switching of a Two-Level-System

Response of the electronic current through an Aharonov-Bohm ring after a two-level-system is switched on is calculated perturbatively by use of non-equilibrium Green function. In the ballistic case the amplitude of the Aharonov-Bohm oscillation is shown to decay to a new equilibrium value due to scattering into other electronic states. Relaxation of Altshuler-Aronov-Spivak oscillation in diffusive case due to dephasing effect is also calculated. The time scale of the relaxation is determined by characteristic relaxation times of the system and the splitting of two-level-system. Oscillation phases are not affected. Future experimental studies of current response may give us direct information on characteristic times of mesoscopic systems

Intervention effects and long-term changes in physical activity and cardiometabolic outcomes among children at risk of noncommunicable diseases in South Africa: a cluster-randomized controlled trial and follow-up analysis

INTRODUCTION: Risk factors for noncommunicable diseases such as insufficient physical activity (PA), overweight or hypertension are becoming increasingly predominant among children globally. While school-based interventions are promising preventive strategies, evidence of their long-term effectiveness, especially among vulnerable populations, is scarce. We aim to assess the short-term effects of the physical and health KaziKidz intervention on cardiometabolic risk factors and the long-term, pre-and post-COVID-19 pandemic changes thereof in high-risk children from marginalized communities. METHODS: The intervention was tested in a cluster-randomized controlled trial between January and October 2019 in eight primary schools near Gqeberha, South Africa. Children with overweight, elevated blood pressure, pre-diabetes, and/or borderline dyslipidemia were identified and re-assessed 2 years post-intervention. Study outcomes included accelerometry-measured PA (MVPA), body mass index (BMI), mean arterial pressure (MAP), glucose (HbA1c), and lipid levels (TC to HDL ratio). We conducted mixed regression analyses to assess intervention effects by cardiometabolic risk profile, and Wilcoxon signed-rank tests to evaluate longitudinal changes in the high-risk subpopulation. RESULTS: We found a significant intervention effect on MVPA during school hours for physically inactive children, and among active as well as inactive girls. In contrast, the intervention lowered HbA1c and TC to HDL ratio only in children with glucose or lipid values within the norm, respectively. At follow-up, the intervention effects were not maintained in at-risk children, who showed a decline in MVPA, and an increase in BMI-for-age, MAP, HbA1c and TC to HDL ratio. CONCLUSION: We conclude that schools are key settings in which to promote PA and improve health; however, structural changes are necessary to ensure that effective interventions reach marginalized school populations and achieve sustainable impact

Mesoscopic Stern-Gerlach device to polarize spin currents

Spin preparation and spin detection are fundamental problems in spintronics and in several solid state proposals for quantum information processing. Here we propose the mesoscopic equivalent of an optical polarizing beam splitter (PBS). This interferometric device uses non-dispersive phases (Aharonov-Bohm and Rashba) in order to separate spin up and spin down carriers into distinct outputs and thus it is analogous to a Stern-Gerlach apparatus. It can be used both as a spin preparation device and as a spin measuring device by converting spin into charge (orbital) degrees of freedom. An important feature of the proposed spin polarizer is that no ferromagnetic contacts are used.Comment: Updated to the published versio

In vitro and in vivo activity and cross resistance profiles of novel ruthenium (II) organometallic arene complexes in human ovarian cancer.

Ruthenium complexes offer the potential of reduced toxicity, a novel mechanism of action, non-cross resistance and a different spectrum of activity compared to platinum containing compounds. Thirteen novel ruthenium(II) organometallic arene complexes have been evaluated for activity (in vitro and in vivo) in models of human ovarian cancer, and cross-resistance profiles established in cisplatin and multi-drug-resistant variants. A broad range of IC50 values was obtained (0.5 to >100 microM) in A2780 parental cells with two compounds (RM175 and HC29) equipotent to carboplatin (6 microM), and the most active compound (HC11) equipotent to cisplatin (0.6 microM). Stable bi-dentate chelating ligands (ethylenediamine), a more hydrophobic arene ligand (tetrahydroanthracene) and a single ligand exchange centre (chloride) were associated with increased activity. None of the six active ruthenium(II) compounds were cross-resistant in the A2780cis cell line, demonstrated to be 10-fold resistant to cisplatin/carboplatin by a mechanism involving, at least in part, silencing of MLH1 protein expression via methylation. Varying degrees of cross-resistance were observed in the P-170 glycoprotein overexpressing multi-drug-resistant cell line 2780AD that could be reversed by co-treatment with verapamil. In vivo activity was established with RM175 in the A2780 xenograft together with non-cross-resistance in the A2780cis xenograft and a lack of activity in the 2780AD xenograft. High activity coupled to non cross-resistance in cisplatin resistant models merit further development of this novel group of anticancer compounds

A novel chalcone derivative which acts as a microtubule depolymerising agent and an inhibitor of P-gp and BCRP in in-vitro and in-vivo glioblastoma models

<p>Abstract</p> <p>Background</p> <p>Over the past decades, in spite of intensive search, no significant increase in the survival of patients with glioblastoma has been obtained. The role of the blood-brain barrier (BBB) and especially the activity of efflux pumps belonging to the ATP Binding Cassette (ABC) family may, in part, explain this defect.</p> <p>Methods</p> <p>The <it>in-vitro </it>activities of JAI-51 on cell proliferation were assessed by various experimental approaches in four human and a murine glioblastoma cell lines. Using drug exclusion assays and flow-cytometry, potential inhibitory effects of JAI-51 on P-gp and BCRP were evaluated in sensitive or resistant cell lines. JAI-51 activity on <it>in-vitro </it>microtubule polymerization was assessed by tubulin polymerization assay and direct binding measurements by analytical ultracentrifugation. Finally, a model of C57BL/6 mice bearing subcutaneous GL26 glioblastoma xenografts was used to assess the activity of the title compound <it>in vivo</it>. An HPLC method was designed to detect JAI-51 in the brain and other target organs of the treated animals, as well as in the tumours.</p> <p>Results</p> <p>In the four human and the murine glioblastoma cell lines tested, 10 μM JAI-51 inhibited proliferation and blocked cells in the M phase of the cell cycle, via its activity as a microtubule depolymerising agent. This ligand binds to tubulin with an association constant of 2 × 10⁵M^-1, overlapping the colchicine binding site. JAI-51 also inhibited the activity of P-gp and BCRP, without being a substrate of these efflux pumps. These <it>in vitro </it>studies were reinforced by our <it>in vivo </it>investigations of C57BL/6 mice bearing GL26 glioblastoma xenografts, in which JAI-51 induced a delay in tumour onset and a tumour growth inhibition, following intraperitoneal administration of 96 mg/kg once a week. In accordance with these results, JAI-51 was detected by HPLC in the tumours of the treated animals. Moreover, JAI-51 was detected in the brain, showing that the molecule is also able to cross the BBB.</p> <p>Conclusion</p> <p>These <it>in vitro </it>and <it>in vivo </it>data suggest that JAI-51 could be a good candidate for a new treatment of tumours of the CNS. Further investigations are in progress to associate the title compound chemotherapy to radiotherapy in a rat model.</p

Randomized Clinical Trial of Laparoscopic Versus Open Repair of the Perforated Peptic Ulcer: The LAMA Trial

Background: Laparoscopic surgery has become popular during the last decade, mainly because it is associated with fewer postoperative complications than the conventional open appr

Interactive models of communication at the nanoscale using nanoparticles that talk to one another

[EN] 'Communication' between abiotic nanoscale chemical systems is an almost-unexplored field with enormous potential. Here we show the design and preparation of a chemical communication system based on enzyme-powered Janus nanoparticles, which mimics an interactive model of communication. Cargo delivery from one nanoparticle is governed by the biunivocal communication with another nanoparticle, which involves two enzymatic processes and the interchange of chemical messengers. The conceptual idea of establishing communication between nanodevices opens the opportunity to develop complex nanoscale systems capable of sharing information and cooperating.A. L.-L. is grateful to 'La Caixa' Banking Foundation for his PhD fellowship. We wish to thank the Spanish Government (MINECO Projects MAT2015-64139-C4-1, CTQ2014-58989-P and CTQ2015-71936-REDT and AGL2015-70235-C2-2-R) and the Generalitat Valenciana (Project PROMETEOII/2014/047) for support. 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Computing, Design, Art: Reflections on an Innovative Moment in History

The paper is concerned with the role of art and design in the history and philosophy of computing. It offers insights arising from research into a period in the 1960s and 70s, particularly in the UK, when computing became more available to artists and designers, focusing on John Lansdown (1929-1999) and Bruce Archer (1922-2005) in London. Models of computing interacted with conceptualisations of art, design and related creative activities in important ways