1,119 research outputs found

    Construction of Special Solutions for Nonintegrable Systems

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    The Painleve test is very useful to construct not only the Laurent series solutions of systems of nonlinear ordinary differential equations but also the elliptic and trigonometric ones. The standard methods for constructing the elliptic solutions consist of two independent steps: transformation of a nonlinear polynomial differential equation into a nonlinear algebraic system and a search for solutions of the obtained system. It has been demonstrated by the example of the generalized Henon-Heiles system that the use of the Laurent series solutions of the initial differential equation assists to solve the obtained algebraic system. This procedure has been automatized and generalized on some type of multivalued solutions. To find solutions of the initial differential equation in the form of the Laurent or Puiseux series we use the Painleve test. This test can also assist to solve the inverse problem: to find the form of a polynomial potential, which corresponds to the required type of solutions. We consider the five-dimensional gravitational model with a scalar field to demonstrate this.Comment: LaTeX, 14 pages, the paper has been published in the Journal of Nonlinear Mathematical Physics (http://www.sm.luth.se/math/JNMP/

    Increasing survival gap between young and elderly gastric cancer patients

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    INTRODUCTION: This study investigates the treatment and survival of young versus elderly potentially curable gastric cancer patients in the Netherlands. PATIENTS AND METHODS: All noncardia gastric cancer patients with potentially curable gastric cancer according to stage (cTx-3, cNx-3, and cMx-0) diagnosed between 1989 and 2013 were selected from the Netherlands Cancer Registry. Trends in treatment and overall survival were compared between young patients (younger than 70 years) and elderly patients (70 years or older). Multivariable logistic regression analysis was used to examine the probability of patients undergoing surgery and chemotherapy in the most recent period. Multivariable Cox regression analysis was used to identify independent factors associated with survival. RESULTS: In total, 8107 young and 13,814 elderly gastric cancer patients were included. There was a major increase in the proportion of patients treated with resection and chemotherapy after 2004-2008. In young patients the increase was from 2.6% in 1999-2003 to 63% in 2009-2013 (p < 0.01). Also an increase was noticed among elderly patients, from 0.1% to 16% (p < 0.01). Median survival increased from 2004 to 2008 onward particularly in young patients and to a lesser extent in elderly patients (from 28 to 41 months vs from 11 to 13 months). Multivariable Cox regression analyses confirmed that overall survival improved for young and elderly patients. DISCUSSION: Young patients experienced a stronger improvement in survival than elderly patients, resulting in an increasing survival gap. The literature shows this is a problem not only in the Netherlands but also throughout Europe. The dissimilarity in treatment between young and elderly patients could be the reason for this difference

    Chronic psychosocial and financial burden accelerates 5-year telomere shortening: findings from the Coronary Artery Risk Development in Young Adults Study.

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    Leukocyte telomere length, a marker of immune system function, is sensitive to exposures such as psychosocial stressors and health-maintaining behaviors. Past research has determined that stress experienced in adulthood is associated with shorter telomere length, but is limited to mostly cross-sectional reports. We test whether repeated reports of chronic psychosocial and financial burden is associated with telomere length change over a 5-year period (years 15 and 20) from 969 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a longitudinal, population-based cohort, ages 18-30 at time of recruitment in 1985. We further examine whether multisystem resiliency, comprised of social connections, health-maintaining behaviors, and psychological resources, mitigates the effects of repeated&nbsp;burden on telomere attrition over 5 years. Our results indicate that adults with high chronic burden do not show decreased telomere length over the 5-year period. However, these effects do vary by level of resiliency, as regression results revealed a significant interaction between chronic burden and multisystem resiliency. For individuals with high repeated&nbsp;chronic burden and low multisystem resiliency (1 SD below the mean), there was a significant 5-year shortening in telomere length, whereas no significant relationships between chronic burden and attrition were evident for those at moderate and higher levels of resiliency. These effects apply similarly across the three components of resiliency. Results imply that interventions should focus on establishing strong social connections, psychological resources, and health-maintaining behaviors when attempting to ameliorate stress-related decline in telomere length among at-risk individuals

    Prognostic value of patient-reported quality of life for survival in oesophagogastric cancer:Analysis from the population-based POCOP study

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    BACKGROUND: Accumulating evidence of trials demonstrates that patient-reported health-related quality of life (HRQoL) at diagnosis is prognostic for overall survival (OS) in oesophagogastric cancer. However, real-world data are lacking. Moreover, differences in disease stages and tumour-specific symptoms are usually not taken into consideration. The aim of this population-based study was to assess the prognostic value of HRQoL, including tumour-specific scales, on OS in patients with potentially curable and advanced oesophagogastric cancer. METHODS: Data were derived from the Netherlands Cancer Registry and the patient reported outcome registry (POCOP). Patients included in POCOP between 2016 and 2018 were stratified for potentially curable (cT1-4aNallM0) or advanced (cT4b or cM1) disease. HRQoL was measured with the EORTC QLQ-C30 and the tumour-specific OG25 module. Cox proportional hazards models assessed the impact of HRQoL, sociodemographic and clinical factors (including treatment) on OS. RESULTS: In total, 924 patients were included. Median OS was 38.9 months in potentially curable patients (n = 795) and 10.6 months in patients with advanced disease (n = 129). Global Health Status was independently associated with OS in potentially curable patients (HR 0.89, 99%CI 0.82-0.97), together with several other HRQoL items: appetite loss, dysphagia, eating restrictions, odynophagia, and body image. In advanced disease, the Summary Score was the strongest independent prognostic factor (HR 0.75, 99%CI 0.59-0.94), followed by fatigue, pain, insomnia and role functioning. CONCLUSION: In a real-world setting, HRQoL was prognostic for OS in patients with potentially curable and advanced oesophagogastric cancer. Several HRQoL domains, including the Summary Score and several OG25 items, could be used to develop or update prognostic models

    Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

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    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

    The PHENIX Experiment at RHIC

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    The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

    Functional Interactions between KCNE1 C-Terminus and the KCNQ1 Channel

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    The KCNE1 gene product (minK protein) associates with the cardiac KvLQT1 potassium channel (encoded by KCNQ1) to create the cardiac slowly activating delayed rectifier, IKs. Mutations throughout both genes are linked to the hereditary cardiac arrhythmias in the Long QT Syndrome (LQTS). KCNE1 exerts its specific regulation of KCNQ1 activation via interactions between membrane-spanning segments of the two proteins. Less detailed attention has been focused on the role of the KCNE1 C-terminus in regulating channel behavior. We analyzed the effects of an LQT5 point mutation (D76N) and the truncation of the entire C-terminus (Δ70) on channel regulation, assembly and interaction. Both mutations significantly shifted voltage dependence of activation in the depolarizing direction and decreased IKs current density. They also accelerated rates of channel deactivation but notably, did not affect activation kinetics. Truncation of the C-terminus reduced the apparent affinity of KCNE1 for KCNQ1, resulting in impaired channel formation and presentation of KCNQ1/KCNE1 complexes to the surface. Complete saturation of KCNQ1 channels with KCNE1-Δ70 could be achieved by relative over-expression of the KCNE subunit. Rate-dependent facilitation of K+ conductance, a key property of IKs that enables action potential shortening at higher heart rates, was defective for both KCNE1 C-terminal mutations, and may contribute to the clinical phenotype of arrhythmias triggered by heart rate elevations during exercise in LQTS mutations. These results support several roles for KCNE1 C-terminus interaction with KCNQ1: regulation of channel assembly, open-state destabilization, and kinetics of channel deactivation

    Impact of Age and Comorbidity on Choice and Outcome of Two Different Treatment Options for Patients with Potentially Curable Esophageal Cancer

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    PURPOSE: This study was designed to assess the impact of age and comorbidity on choice and outcome of definitive chemoradiotherapy (dCRT) or neoadjuvant chemoradiotherapy plus surgery. METHODS: In this population-based study, all patients with potentially curable EC (cT1N+/cT2-3, TX, any cN, cM0) diagnosed in the South East of the Netherlands between 2004 and 2014 were included. Kaplan-Meier method with log-rank tests and multivariable Cox regression analysis were used to compare overall survival (OS). RESULTS: A total of 702 patients was included. Age ≥ 75 years and multiple comorbidities were associated with a higher probability for dCRT (odds ratio [OR] 8.58; 95% confidence interval [CI] 4.72-15.58; and OR 3.09; 95% CI 1.93-4.93). The strongest associations were found for the combination of hypertension plus diabetes (OR 3.80; 95% CI 1.97-7.32) and the combination of cardiovascular with pulmonary comorbidity (OR 3.18; 95% CI 1.57-6.46). Patients with EC who underwent dCRT had a poorer prognosis than those who underwent nCRT plus surgery, irrespective of age, number, and type of comorbidities. In contrast, for patients with squamous cell carcinoma with ≥ 2 comorbidities or age ≥ 75 years, OS was comparable between both groups (hazard ratio [HR] 1.52; 95% CI 0.78-2.97; and HR 0.73; 95% CI 0.13-4.14). CONCLUSIONS: Histological tumor type should be acknowledged in treatment choices for patients with esophageal cancer. Neoadjuvant chemoradiotherapy plus surgery should basically be advised as treatment of choice for operable esophageal adenocarcinoma patients. For patients with esophageal squamous cell carcinoma with ≥ 2 comorbidities or age ≥ 75 years, dCRT may be the preferred strategy
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