112 research outputs found

    Correction to probing the quantum states of a single atom transistor at microwave frequencies

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    Abstract not availableGiuseppe Carlo Tettamanzi, Samuel James Hile, Matthew Gregory House, Martin Fuechsle, Sven Rogge, and Michelle Y. Simmon

    Hepatic Steatosis After Neoadjuvant Chemotherapy for Pancreatic Cancer: Incidence and Implications for Outcomes After Pancreatoduodenectomy

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    This article is made available for unrestricted research re-use and secondary analysis in any form or be any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemicBackground This study aimed to determine the incidence of new onset hepatic steatosis after neoadjuvant chemotherapy for pancreatic cancer and its impact on outcomes after pancreatoduodenectomy. Methods Retrospective review identified patients who received neoadjuvant chemotherapy for pancreatic adenocarcinoma and underwent pancreatoduodenectomy from 2013 to 2018. Preoperative computed tomography scans were evaluated for the development of hepatic steatosis after neoadjuvant chemotherapy. Hypoattenuation included liver attenuation greater than or equal to 10 Hounsfield units less than tissue density of spleen on noncontrast computed tomography and greater than or equal to 20 Hounsfield units less on contrast-enhanced computed tomography. Results One hundred forty-nine patients received neoadjuvant chemotherapy for a median of 5 cycles (interquartile range (IQR), 4–6). FOLFIRINOX was the regimen in 78% of patients. Hepatic steatosis developed in 36 (24%) patients. The median time from neoadjuvant chemotherapy completion to pancreatoduodenectomy was 40 days (IQR, 29–51). Preoperative biliary stenting was performed in 126 (86%) patients. Neoadjuvant radiotherapy was delivered to 23 (15%) patients. Female gender, obesity, and prolonged exposure to chemotherapy were identified as risk factors for chemotherapy-associated hepatic steatosis. Compared with control patients without neoadjuvant chemotherapy-associated hepatic steatosis, patients developing steatosis had similar rates of postoperative pancreatic fistula (8% (control) vs. 4%, p = 0.3), delayed gastric emptying (8% vs. 14%, p = 0.4), and major morbidity (11% vs. 15%, p = 0.6). Ninety-day mortality was similar between groups (8% vs. 2%, p = 0.08). Conclusion Hepatic steatosis developed in 24% of patients who received neoadjuvant chemotherapy but was not associated with increased morbidity or mortality after pancreatoduodenectomy

    Optimal hepatobiliary scintigraphy for gallbladder dyskinesia

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    Background: The accuracy of hepatobiliary scintigraphy to assess gallbladder function remains controversial. National supply shortages of pharmaceutical-grade cholecystokinin led to the use of an oral fatty meal to stimulate gallbladder contraction during hepatobiliary scintigraphy. The goal of this study was to compare the predictive indices of cholecystokinin and fatty meal ingestion for stimulation of gallbladder contraction. Methods: Patients evaluated with hepatobiliary iminodiacetic acid scan from 2014 to 2017 were reviewed and grouped based on testing stimulant (fatty meal versus cholecystokinin). Patients who later underwent cholecystectomy were selected for analysis. Hepatobiliary iminodiacetic acid results were correlated with surgical pathology and postoperative resolution of symptoms. Two-way statistical analysis was performed. Results: A total of 359 patients underwent hepatobiliary iminodiacetic acid scan followed by cholecystectomy for biliary dyskinesia. Patients who received fatty meal stimulant (n = 86) were compared to those that received cholecystokinin (n = 273). Mean gallbladder ejection fraction during hepatobiliary iminodiacetic acid was 38% and 44% for the cholecystokinin and fatty meal groups, respectively, P = .073. Predictive metrics were not statistically different between groups with regard to pathology, symptomatic improvement, or accuracy. Symptomatic resolution (cholecystokinin-hepatobiliary iminodiacetic acid 78%, fatty meal-hepatobiliary iminodiacetic acid 68%; P = 0.058) and specificity (cholecystokinin-hepatobiliary iminodiacetic acid 26%, fatty meal-hepatobiliary iminodiacetic acid 44%, P = 0.417) were comparable in both testing groups. Conclusion: Stimulation of gallbladder contraction with a fatty meal during hepatobiliary iminodiacetic acid testing is a more affordable and reliable alternative to cholecystokinin for patients undergoing evaluation for gallbladder dysmotility

    Optimum electrode configurations for fast ion separation in microfabricated surface ion traps

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    For many quantum information implementations with trapped ions, effective shuttling operations are important. Here we discuss the efficient separation and recombination of ions in surface ion trap geometries. The maximum speed of separation and recombination of trapped ions for adiabatic shuttling operations depends on the secular frequencies the trapped ion experiences in the process. Higher secular frequencies during the transportation processes can be achieved by optimising trap geometries. We show how two different arrangements of segmented static potential electrodes in surface ion traps can be optimised for fast ion separation or recombination processes. We also solve the equations of motion for the ion dynamics during the separation process and illustrate important considerations that need to be taken into account to make the process adiabatic

    Designing spin-spin interactions with one and two dimensional ion crystals in planar micro traps

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    We discuss the experimental feasibility of quantum simulation with trapped ion crystals, using magnetic field gradients. We describe a micro structured planar ion trap, which contains a central wire loop generating a strong magnetic gradient of about 20 T/m in an ion crystal held about 160 \mu m above the surface. On the theoretical side, we extend a proposal about spin-spin interactions via magnetic gradient induced coupling (MAGIC) [Johanning, et al, J. Phys. B: At. Mol. Opt. Phys. 42 (2009) 154009]. We describe aspects where planar ion traps promise novel physics: Spin-spin coupling strengths of transversal eigenmodes exhibit significant advantages over the coupling schemes in longitudinal direction that have been previously investigated. With a chip device and a magnetic field coil with small inductance, a resonant enhancement of magnetic spin forces through the application of alternating magnetic field gradients is proposed. Such resonantly enhanced spin-spin coupling may be used, for instance, to create Schr\"odinger cat states. Finally we investigate magnetic gradient interactions in two-dimensional ion crystals, and discuss frustration effects in such two-dimensional arrangements.Comment: 20 pages, 13 figure

    The charismatic leadership of the ECB presidency:A language-based analysis

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    There is little doubt that the European Central Bank (ECB), and in particular its presidency, has taken the lead in tackling the euro crisis. But can this leadership be also characterised as charismatic? This article answers the question by focusing on language – a key component as well as a reliable indicator of charisma. By means of a software‐assisted content analysis of the entire corpus of ECB presidential speeches, it is found that the crisis has indeed led to the emergence of the Bank's presidency as a charismatic euro leader. This in turn confirms the recent politicisation of the ECB, but at the same time might be seen as mitigating the problems related to the Bank's democratic deficit, to the extent that charisma can be seen, from a Weberian standpoint, as an alternative source of political legitimacy

    Democracy, Globalization and Private Investment in Ghana

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    The article examines the effects of democracy and globalization on private investment in Ghana for the period 1980–2012, using the autoregressive distributed lag (ARDL) bounds test for cointegration and the error correction model (ECM). Two models are used. In Model 1, democracy is proxy by an index for institutional quality (Polity 2), while Model 2 uses an index for civil liberties as proxy for democracy. The results for Model 1 show globalization and public investment increase private investment, while exchange rate volatility and trade openness decrease private investment in both the long and short run. In addition, national income and interest rate reduce private investment in the short run. In the case of Model 2, credit to the private sector and public investment increase private investment, while exchange rate volatility and trade openness decrease private investment in both the long and short run. Finally, national income and interest rate reduce private investment in the short run. The findings and policy recommendations of the article provide vital information for policy implementation in Ghana

    Modeling infectious disease dynamics in the complex landscape of global health.

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    Despite some notable successes in the control of infectious diseases, transmissible pathogens still pose an enormous threat to human and animal health. The ecological and evolutionary dynamics of infections play out on a wide range of interconnected temporal, organizational, and spatial scales, which span hours to months, cells to ecosystems, and local to global spread. Moreover, some pathogens are directly transmitted between individuals of a single species, whereas others circulate among multiple hosts, need arthropod vectors, or can survive in environmental reservoirs. Many factors, including increasing antimicrobial resistance, increased human connectivity and changeable human behavior, elevate prevention and control from matters of national policy to international challenge. In the face of this complexity, mathematical models offer valuable tools for synthesizing information to understand epidemiological patterns, and for developing quantitative evidence for decision-making in global health

    Hypertensive conditions of pregnancy, preterm birth, and premenopausal breast cancer risk: a premenopausal breast cancer collaborative group analysis

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    Purpose: Women with preeclampsia are more likely to deliver preterm. Reports of inverse associations between preeclampsia and breast cancer risk, and positive associations between preterm birth and breast cancer risk are difficult to reconcile. We investigated the co-occurrence of preeclampsia/gestational hypertension with preterm birth and breast cancer risk using data from the Premenopausal Breast Cancer Collaborative Group. Methods: Across 6 cohorts, 3096 premenopausal breast cancers were diagnosed among 184,866 parous women. We estimated multivariable hazard ratios (HR) and 95% confidence intervals (CI) for premenopausal breast cancer risk using Cox proportional hazards regression. Results: Overall, preterm birth was not associated (HR 1.02, 95% CI 0.92, 1.14), and preeclampsia was inversely associated (HR 0.86, 95% CI 0.76, 0.99), with premenopausal breast cancer risk. In stratified analyses using data from 3 cohorts, preterm birth associations with breast cancer risk were modified by hypertensive conditions in first pregnancies (P-interaction = 0.09). Preterm birth was positively associated with premenopausal breast cancer in strata of women with preeclampsia or gestational hypertension (HR 1.52, 95% CI: 1.06, 2.18), but not among women with normotensive pregnancy (HR = 1.09, 95% CI: 0.93, 1.28). When stratified by preterm birth, the inverse association with preeclampsia was more apparent, but not statistically different (P-interaction = 0.2), among women who did not deliver preterm (HR = 0.82, 95% CI 0.68, 1.00) than those who did (HR = 1.07, 95% CI 0.73, 1.56). Conclusion: Findings support an overall inverse association of preeclampsia history with premenopausal breast cancer risk. Estimates for preterm birth and breast cancer may vary according to other conditions of pregnancy

    Palaeoenvironmental control on distribution of crinoids in the Bathonian (Middle Jurassic) of England and France

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    Bulk sampling of a number of different marine and marginal marine lithofacies in the British Bathonian has allowed us to assess the palaeoenvironmental distribution of crinoids for the first time. Although remains are largely fragmentary, many species have been identified by comparison with articulated specimens from elsewhere, whilst the large and unbiased sample sizes allowed assessment of relative proportions of different taxa. Results indicate that distribution of crinoids well corresponds to particular facies. Ossicles of Chariocrinus and Balanocrinus dominate in deeper-water and lower-energy facies,with the former extending further into shallower-water facies than the latter. Isocrinus dominates in shallower water carbonate facies, accompanied by rarer comatulids, and was also present in the more marine parts of lagoons. Pentacrinites remains are abundant in very high-energy oolite shoal lithofacies. The presence of millericrinids within one, partly allochthonous lithofacies suggests the presence of an otherwise unknown hard substrate from which they have been transported. These results are compared to crinoid assemblages from other Mesozoic localities, and it is evident that the same morphological ad-aptations are present within crinoids from similar lithofacies throughout the Jurassic and Early Cretaceous
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