20,449 research outputs found

    Complete gate control of supercurrent in graphene p-n junctions

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    In a conventional Josephson junction of graphene, the supercurrent is not turned off even at the charge neutrality point, impeding further development of superconducting quantum information devices based on graphene. Here we fabricate bipolar Josephson junctions of graphene, in which a p-n potential barrier is formed in graphene with two closely spaced superconducting contacts, and realize supercurrent ON/OFF states using electrostatic gating only. The bipolar Josephson junctions of graphene also show fully gate-driven macroscopic quantum tunnelling behaviour of Josephson phase particles in a potential well, where the confinement energy is gate tuneable. We suggest that the supercurrent OFF state is mainly caused by a supercurrent dephasing mechanism due to a random pseudomagnetic field generated by ripples in graphene, in sharp contrast to other nanohybrid Josephson junctions. Our study may pave the way for the development of new gate-tuneable superconducting quantum information devices.open114344sciescopu

    Next Generation Sequencing Assay for Detection of Circulating HPV DNA (cHPV-DNA) in Patients Undergoing Radical (Chemo)Radiotherapy in Anal Squamous Cell Carcinoma (ASCC).

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    Background: Following chemo-radiotherapy (CRT) for human papilloma virus positive (HPV+) anal squamous cell carcinoma (ASCC), detection of residual/recurrent disease is challenging. Patients frequently undergo unnecessary repeated biopsies for abnormal MRI/clinical findings. In a pilot study we assessed the role of circulating HPV-DNA in identifying "true" residual disease. Methods: We prospectively collected plasma samples at baseline (n = 21) and 12 weeks post-CRT (n = 17). Circulating HPV-DNA (cHPV DNA) was measured using a novel next generation sequencing (NGS) assay, panHPV-detect, comprising of two primer pools covering distinct regions of eight high-risk HPV genomes (16, 18, 31, 33, 35, 45, 52, and 58) to detect circulating HPV-DNA (cHPV DNA). cHPV-DNA levels post-CRT were correlated to disease response. Results: In pre-CRT samples, panHPV-detect demonstrated 100% sensitivity and specificity for HPV associated ASCC. PanHPV-detect was able to demonstrate cHPV-DNA in 100% (9/9) patients with T1/T2N0 cancers. cHPV-DNA was detectable 12 weeks post CRT in just 2/17 patients, both of whom relapsed. 1/16 patients who had a clinical complete response (CR) at 3 months post-CRT but relapsed at 9 months and 1/1 patient with a partial response (PR). PanHPV-detect demonstrated 100% sensitivity and specificity in predicting response to CRT. Conclusion: We demonstrate that panHPV-detect, an NSG assay is a highly sensitive and specific test for the identification of cHPV-DNA in plasma at diagnosis. cHPV-DNA post-treatment may predict clinical response to CRT

    Aerosol modulation of ultraviolet radiation dose over four metro cities in India

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    This paper discusses the influence of aerosols on UV erythemal dose over four metro cities in India. Tropospheric Emission Monitoring Internet Service (TEMIS), archived UV-index (UV-I), and UV daily erythemal dose obtained from SCIAMACHY satellite were used in this study during June 2004 and May 2005 periods covering four important Indian seasons. UV-Index (UV-I), an important parameter representing UV risk, was found to be in the high to extreme range in Chennai (8.1 to 15.33), moderate to extreme range in Mumbai and Kolkata (5 to 16.5), and low to extreme over Delhi (3 to 15). Average UV erythemal dose showed seasonal variation from 5.9 to 6.3ā€‰KJmāˆ’2 during summer, 2.9 to 4.4ā€‰KJmāˆ’2 during postmonsoon, 3 to 4.5ā€‰KJmāˆ’2 during winter, and 5.1 to 6.19ā€‰KJmāˆ’2 during premonsoon seasons over the four cities. To estimate the influence of aerosols on reducing UV dose, UV aerosol radiative forcing and forcing efficiency were estimated over the sites. The average aerosol forcing efficiency was found to be from to ā€‰KJmāˆ’2 AODāˆ’1 on different seasons. The study suggests that aerosols can reduce the incoming UV radiation dose by 30ā€“60% during different seasons

    Quantum Common Causes and Quantum Causal Models

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    Reichenbachā€™s principle asserts that if two observed variables are found to be correlated, then there should be a causal explanation of these correlations. Furthermore, if the explanation is in terms of a common cause, then the conditional probability distribution over the variables given the complete common cause should factorize. The principle is generalized by the formalism of causal models, in which the causal relationships among variables constrain the form of their joint probability distribution. In the quantum case, however, the observed correlations in Bell experiments cannot be explained in the manner Reichenbachā€™s principle would seem to demand. Motivated by this, we introduce a quantum counterpart to the principle. We demonstrate that under the assumption that quantum dynamics is fundamentally unitary, if a quantum channel with input A and outputs B and C is compatible with A being a complete common cause of B and C , then it must factorize in a particular way. Finally, we show how to generalize our quantum version of Reichenbachā€™s principle to a formalism for quantum causal models and provide examples of how the formalism works

    Interferon dysregulation and virus-induced cell death in avian influenza H5N1 virus infections.

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    1. Hyper-induction of cytokines and chemokines was found in human blood macrophages infected with the avian influenza H5N1 and H9N2/G1 viruses, as compared to those infected with human influenza H1N1 virus. 2. IRF3 played a significant role in the hyperinduction of cytokines including IFN-Ī², IFN-Ī»1,IFN-Ī± subtypes, MCP-1, and TNF-Ī±, and also played a part in subsequent cytokine-induced cell signalling cascades. 3. Compared with H1N1 viruses, avian influenza viruses including H5N1/97 and its precursors triggered a caspase-mediated but delayed apoptotic response in human macrophages. 4. Therapies that can minimise immunopathology-associated dysregulation of innate immunity without impairing effective host defence may be valuable adjuncts to antiviral therapy.published_or_final_versio

    The isolation of VCAM-1+ endothelial cell-derived extracellular vesicles using microfluidics

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    Background:Ā Vascular cell adhesion molecule-1 (VCAM-1+) endothelial cell-derived extracellular vesicles (EC-EVs) are augmented in cardiovascular disease, where they can signal the deployment of immune cells from the splenic reserve. Endothelial cells in culture activated with pro-inflammatory tumor necrosis factor-Ī± (TNF-a) also release VCAM-1+Ā EC-EVs. However, isolating VCAM-1+Ā EC-EVs from conditioned cell culture media for subsequent in-depth analysis remains challenging. Aim:Ā We utilized the extracellular vesicles (EV) microfluidics herringbone chip (EVHB-Chip), coated with anti-VCAM-1 antibodies, for selective capture of VCAM-1+Ā cells and EC-EVs. Methods and Results:Ā Engineered EA.hy926 endothelial cells overexpressing VCAM-1 (PĀ < 0.001 versus control) showed increased binding to the VCAM-1-Ā EVHB-Chip versus an IgG device. TNF-Ī±-stimulated human umbilical cord vein endothelial cells (HUVECs) exhibited elevated VCAM-1 protein levels (PĀ < 0.001) and preferential binding to the VCAM-1-Ā EVHB-Chip versus the IgG device. HUVECs stimulated with TNF-Ī± showed differential gene expression of intercellular adhesion molecule-1 (ICAM-1) (PĀ < 0.001) and VCAM-1 (PĀ < 0.001) by digital droplet PCR versus control cells. HUVEC-derived EC-EVs were positive for CD9, CD63, HSP70, and ALIX and had a modal size of 83.5 nm. Control and TNF-Ī±-stimulated HUVEC-derived EC-EV cultures were captured on the VCAM-1-Ā EVHB-Chip, demonstrating selective capture. VCAM-1+Ā EC-EV were significantly enriched for ICAM-1 (PĀ < 0.001) mRNA transcripts. Conclusion:Ā This study presents a novel approach using theĀ EVHB-Chip, coated with anti-VCAM-1 antibodies and digital droplet PCR for the study of VCAM-1+Ā EC-EVs. Isolation of VCAM-1+Ā EC-EV from heterogeneous sources such as conditioned cell culture media holds promise for subsequent detailed characterization, and may facilitate the study of VCAM-1+Ā EC-EVs in cardiovascular and metabolic diseases, for disease monitoring and therapeutic insights

    A comparison of the cost-effectiveness of treatment of prolonged acute convulsive epileptic seizures in children across Europe

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    In the majority of children and adolescents with epilepsy, optimal drug therapy adequately controls their condition. However, among the remaining patients who are still uncontrolled despite mono-, bi- or tri-therapy with chronic anti-epileptic treatment, a rescue medication is required. In Western Europe, the licensed medications available for first-line treatment of prolonged acute convulsive seizures (PACS) vary widely, and so comparators for clinical and economic evaluation are not consistent. No European guidelines currently exist for the treatment of PACS in children and adolescents and limited evidence is available for the effectiveness of treatments in the community setting. The authors present cost-effectiveness data for BUCCOLAMĀ® (midazolam oromucosal solution) for the treatment of PACS in children and adolescents in the context of the treatment pathway in seven European countries in patients from 6 months to 18 years. For each country, the health economic model consisted of a decision tree, with decision nodes informed by clinical data and expert opinion obtained via a Delphi methodology. The events modelled are those associated with a patient experiencing a seizure in the community setting. The model assessed the likelihood of medication being administered successfully and of seizure cessation. The associated resource use was also modelled, and ambulance call-outs and hospitalisations were considered. The patient's quality of life was estimated by clinicians, who completed a five-level EuroQol five dimensions questionnaire from the perspective of a child or adolescent suffering a seizure. Despite differences in current therapy, treatment patterns and healthcare costs in all countries assessed, BUCCOLAM was shown to be cost saving and offered increased health-related benefits for patients in the treatment of PACS compared with the current local standard of care
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