A Coupled FEM-BEM Approach for the Solution of the Free-Boundary Axi-Symmetric Plasma Equilibrium Problem

In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.     

Numerical Integrators for Dispersion-Managed KdV Equation

In this paper, we consider the numerics of the dispersion-managed Korteweg-de Vries (DM-KdV) equation for describing wave propagations in inhomogeneous media. The DM-KdV equation contains a variable dispersion map with discontinuity, which makes the solution non-smooth in time. We formally analyze the convergence order reduction problems of some popular numerical methods including finite difference and time-splitting for solving the DM-KdV equation, where a necessary constraint on the time step has been identified. Then, two exponential-type dispersion-map integrators up to second order accuracy are derived, which are efficiently incorporated with the Fourier pseudospectral discretization in space, and they can converge regardless of the discontinuity and the step size. Numerical comparisons show the advantage of the proposed methods with the application to solitary wave dynamics and extension to the fast & strong dispersion-management regime.     

Temperature-controlled power modulation compensates for heterogeneous nanoparticle distributions: a computational optimization analysis for magnetic hyperthermia

Purpose: To study, with computational models, the utility of power modulation to reduce tissue temperature heterogeneity for variable nanoparticle distributions in magnetic nanoparticle hyperthermia.

Methods: Tumour and surrounding tissue were modeled by elliptical two- and three-dimensional computational phantoms having six different nanoparticle distributions. Nanoparticles were modeled as point heat sources having amplitude-dependent loss power. The total number of nanoparticles was fixed, and their spatial distribution and heat output were varied. Heat transfer was computed by solving the Pennes’ bioheat equation using finite element methods (FEM) with temperature-dependent blood perfusion. Local temperature was regulated using a proportional-integral-derivative (PID) controller. Tissue temperature, thermal dose and tissue damage were calculated. The required minimum thermal dose delivered to the tumor was kept constant, and heating power was adjusted for comparison of both the heating methods.

Results: Modulated power heating produced lower and more homogeneous temperature distributions than did constant power heating for all studied nanoparticle distributions. For a concentrated nanoparticle distribution, located off-center within the tumor, the maximum temperatures inside the tumor were 16% lower for modulated power heating when compared to constant power heating. This resulted in less damage to surrounding normal tissue. Modulated power heating reached target thermal doses up to nine-fold more rapidly when compared to constant power heating.

Conclusions: Controlling the temperature at the tumor-healthy tissue boundary by modulating the heating power of magnetic nanoparticles demonstrably compensates for a variable nanoparticle distribution to deliver effective treatment.     

重庆地区3～12岁儿童肺通气功能预计方程式的初步建立

目的　建立学龄前期及小学阶段学龄期儿童的肺通气功能参数预计方程式。方法　采用德国JAEGER公司MasterScreen Pead肺功能仪，于2017年4月至2018年9月对重庆地区主城两所幼儿园及小学的458名3～12岁儿童进行肺通气功能测定。采用SAS9.4统计软件包，通过单因素线性回归模型分析各已知及潜在的影响因素与各肺功能参数的相关性，以各肺功能指标实测值为因变量，以性别、年龄、身高、体重为自变量，通过多元逐步回归建立线性回归方程。将构建的方程式与文献中相应年龄段的肺功能预计方程式进行比较，采用相对预测误差平均值评价各公式的适用性。结果　对于学龄前期儿童，肺功能各指标［剩余25%肺活量时的用力呼气流量（MEF25）除外］均与月龄、身高、体重相关，性别与用力肺活量（FVC）、第0.5秒用力呼气容积（FEV0.5）、第1秒用力呼气容积（FEV1）、呼气峰流速（PEF）、MEF75、MEF50和最大通气量（MVV）相关。对于学龄期儿童，年龄、身高、体重与除呼气中段流速（MMEF）外的各肺功能指标均有显著相关性，性别与FVC、FEV1、FEV0.5/FVC、MEF50、MVV显著相关。预计公式模型比较后显示，该次构建的模型对该研究群体有较好的适用性。结论　年龄、身高和体重为影响学龄前期和学龄期儿童肺通气功能参数的主要变量，性别对学龄前期儿童肺功能参数的影响多于学龄期儿童，应根据不同年龄段建立各项肺通气功能指标的预计公式。该模型的构建可为3～12岁儿童肺通气功能相关参数的预测提供帮助。     

Long-term health and socioeconomic outcome of obstructive sleep apnea in children and adolescents

BackgroundThere is limited information about the long-term outcome of obstructive sleep apnea (OSA) diagnosed in children and adolescents for educational and social factors. Here, we estimate the long-term socioeconomic outcome and health care costs of OSA.MethodsThe historical case-control cohort study included Danish individuals with OSA diagnosed in childhood or adolescence between 1994 and 2015. Health care costs and socioeconomic data were obtained from nationwide administrative and health registers. A total of 5419 were diagnosed during this period; of these we traced 1004 patients who we compared with 4085 controls (mean index age, 10.2 years; Standard Deviation (SD), 5.6 years) until the age of 20 years. Controls were matched for age, gender, and residency.ResultsComparing the OSA patient and control groups at age 20 years we found: 1) lower parental educational level; 2) significantly lower educational level also after adjustment for parental educational level; 3) lower school grade-point averages; 4) lower employment rate and lower income, which was not fully compensated when transfer payments were considered; and 5) patients' initial health care costs were higher due to higher morbidity. Patients showed higher mortality rates than controls (Hazard Ratio (HR) = 7.63, 95% CI = 4.87–11.95, P < 0.001).ConclusionsOSA in children and adolescent is associated with a significant influence on morbidity, mortality, educational level, grading, social outcome, and welfare consequences.     

Patient affect,physician liking for the patient,physician behavior,and patient reported outcomes: A modeling approach

ObjectiveTo determine associations between patient affect and physician liking of the patient, and their associations with physician behavior and patient-reported outcomes.MethodsStructural equation modeling based on coding of 497 videotaped hospital encounters, with questionnaires assessing pre-visit patient affect, post-visit patient affect and encounter evaluations, and physician liking of the patient, involving 71 physicians.ResultsIn first visits, patient reported outcomes were strongly correlated with physician behavior and less so with physician liking, while in later visits, patient reported outcomes were directly related to physician liking and not mediated by physician behavior. Physician liking predicted physician behavior, more for female physicians in first visits. Patient negative affect before the visit was negatively associated with male physicians’ liking. When acquainted, both patient positive and negative affect were associated with physician liking.ConclusionPhysician liking of the patient plays a dynamic role in a consultation, is influenced by patient pre-encounter affect, and influences physician behavior. The dynamics are different in first and later visits, and influenced by physician gender.Practice implicationsPhysicians should be aware how patient affect influences their behavior, and administrators should take any prior relationship between patient and physician into account when evaluating patient reported outcomes.     

Pathways in the association between sugar sweetened beverages and child asthma traits in the 2nd year of life: Findings from the BRISA cohort

Studies on the exposure of children to sugar-sweetened beverages (SSBs) at an early age may contribute to better understand the common causes and the temporal order of the relationships between obesity and asthma in early childhood. The objective of this study was to estimate the association between SSB and child asthma traits in the 2nd year of life, modeling direct and indirect pathways mediated by the highest BMI-z of the child and allergic inflammation. Data from the BRISA cohort, São Luís-MA, Brazil (n = 1140), were obtained from the baseline and from the follow-up performed at the 2nd year of life. The main explanatory variable was the calories from added sugars in SSBs as a percentage of the total daily energy intake. The outcome child asthma traits was a latent variable deduced from four indicators: medical diagnosis of asthma, wheezing, emergency visit due to intense wheezing, and medical diagnosis of rhinitis. A high percentage of daily calories from sugars added to SSBs was directly associated with higher values of child asthma traits (standardized coefficient (SC = 0.073; P = .030)). High levels of eosinophils were also directly associated with child asthma traits (SC = 0.118; P = .049). No mediation pathways were observed via greater BMI-z or eosinophil counts. Therefore, early exposure of children to SSB may contribute to increased risk of childhood asthma, preceding the link between sugar consumption and overweight/obesity, not yet evident in children in the first 2 years of life.