A High Order Bound Preserving Finite Difference Linear Scheme for Incompressible Flows

We propose a high order finite difference linear scheme combined with a high order bound preserving maximum-principle-preserving (MPP) flux limiter to solve the incompressible flow system. For such problem with highly oscillatory structure but not strong shocks, our approach seems to be less dissipative and much less costly than a WENO type scheme, and has high resolution due to a Hermite reconstruction. Spurious numerical oscillations can be controlled by the weak MPP flux limiter. Numerical tests are performed for the Vlasov-Poisson system, the 2D guiding-center model and the incompressible Euler system. The comparison between the linear and WENO type schemes, with and without the MPP flux limiter, will demonstrate the good performance of our proposed approach.     

A Priori Subcell Limiting Approach for the FR/CPR Method on Unstructured Meshes

A priori subcell limiting approach is developed for high-order flux reconstruction/correction procedure via reconstruction (FR/CPR) methods on two-dimensional unstructured quadrilateral meshes. Firstly, a modified indicator based on modal energy coefficients is proposed to detect troubled cells, where discontinuities exist. Then, troubled cells are decomposed into nonuniform subcells and each subcell has one solution point. A second-order finite difference shock-capturing scheme based on nonuniform nonlinear weighted (NNW) interpolation is constructed to perform the calculation on troubled cells while smooth cells are calculated by the CPR method. Numerical investigations show that the proposed subcell limiting strategy on unstructured quadrilateral meshes is robust in shock-capturing.     

Atrial functional tricuspid regurgitation: An underappreciated cause of secondary tricuspid regurgitation

Secondary tricuspid regurgitation (TR) caused by right ventricular enlargement in the setting of left heart disease/pulmonary hypertension has been well described. In contrast, that associated with right atrial enlargement—atrial functional TR (AF‐TR)—remains largely underappreciated. AF‐TR most often occurs in the setting of lone atrial fibrillation, although it is also seen in its absence (idiopathic AF‐TR). Several recent studies have found that the prevalence, hemodynamic significance, and prognosis of AF‐TR are not inconsequential, suggesting increased physician awareness of this novel clinical entity is warranted. This article discusses the pathogenesis, echocardiographic findings, and treatment of this underappreciated cause of secondary TR.     

Effect of a Simple Exercise Program on Hospitalization-Associated Disability in Older Patients: A Randomized Controlled Trial

ObjectiveHospitalization-associated disability [HAD, ie, the loss of ability to perform ≥1 basic activities of daily living (ADLs) independently at discharge] is a frequent condition among older patients. The present study assessed whether a simple inpatient exercise program decreases HAD incidence in acutely hospitalized very old patients.DesignIn this randomized controlled trial (Activity in Geriatric Acute Care) participants were assigned to a control or intervention group and were assessed at baseline, admission, discharge, and 3 months thereafter.Setting and ParticipantsIn total, 268 patients (mean age 88 years, range 75–102) admitted to an acute care for older patients unit of a public hospital were randomized to a control (n = 125) or intervention (exercise) group (n = 143).MethodsBoth groups received usual care, and patients in the intervention group also performed simple supervised exercises (walking and rising from a chair, for a total duration of ∼20 minutes/day). We measured ADL function (Katz index) and incident HAD at discharge and after 3 months (primary outcome) and Short Physical Performance Battery, ambulatory capacity, number of falls, rehospitalization, and death during a 3-month follow-up (secondary outcomes).ResultsMedian duration of hospitalization was 7 days (interquartile range 4 days). The intervention group had a lower risk of HAD with reference to both baseline [odds ratio (OR) 0.36; 95% confidence interval (CI) 0.17–0.76, P = .007] and admission (OR 0.29; 95% CI 0.10–0.89, P = .030). A trend toward an improved ADL function at discharge vs admission was found in the intervention group compared with controls (OR 0.32; 95% CI ‒0.04 to 0.68; P = .083). No between-group differences were noted for the other endpoints (all P > .05).Conclusion and ImplicationsA simple inpatient exercise program decreases risk of HAD in acutely hospitalized, very old patients.     

肿瘤性复杂性胸壁缺损的修复策略及对肿瘤治疗的积极影响

复杂性胸壁缺损的修复一直是一项极具挑战性的工作。肿瘤性复杂性胸壁缺损的修复决策及其执行困难是限制胸壁肿瘤治疗方法选择及影响预后的重要因素之一。皮瓣解剖学研究的深入、胸壁支持结构重建技术的进步、显微外科技术的发展、麻醉护理的发展、对综合治疗的重视和治疗手段的进步等,使传统认为不可切除的胸壁肿瘤得以彻底地切除和安全有效地修复,从而使与缺损修复相关的肿瘤切除及辅助治疗的禁忌证缩减到最小程度,有效地提高了胸壁肿瘤患者的生存质量,并很大程度上延长了生存率。作者以湖南省肿瘤医院整形外科15年565例胸壁肿瘤切除后修复重建的临床资料为依据,充实了胸壁肿瘤切除及修复的策略:(1)可靠的胸壁骨性支架重建;(2)有效的软组织修复;(3)麻醉及护理与手术团队的合作;(4)系统有序的综合治疗。并进一步明确了复杂胸壁肿瘤切除及重建的细节理念,包括胸部肿瘤治疗中加强多学科合作的密切性和科学性,整形外科医生参与肿瘤治疗整体规划的主动性和时机前移等。