Head of the Class: Oxford Health Plans and the Uncertain Future of Class Arbitrability Determinations

Arbitration clauses allow contracting parties to resolve their contractual disputes without being subjected to lengthy and expensive judicial processes. Arbitrators are authorized to interpret contractual arbitration agreements to determine which issues the parties agreed to arbitrate. However, contract arbitration provisions are often silent as to the availability of class action procedures. Oxford Health Plans LLC v. Sutter held that, when parties expressly agree to allow an arbitrator to interpret whether their agreement allows class action arbitration, the arbitrator does not exceed his authority in doing so, regardless of interpretive error.\u27 This note first discusses how the United States Supreme Court resolved a circuit split by distinguishing Stolt-Nielsen4 in Oxford Health Plans. Second, this note discusses a question that the Court raised, but left unanswered: whether an arbitrator or a court should be presumptively responsible for interpreting whether an arbitration agreement allows for class arbitration.\u2

Plurality Influence: Reed Elsevier and the Precedential Value of Bazzle on Class Arbitrability

Class arbitration is a tricky process to navigate as it introduces more parties, higher stakes, and more procedures than typical bilateral arbitration. Because class arbitration is more complex, the determination as to whether an arbitration agreement authorizes class arbitration (class arbitrability) is an important one, and the entity that makes the class determination should be knowledgeable about class procedures in order to be suited to make such an important finding. In Reed Elsevier, Inc. ex rel. LexisNexis Div. v. Crockett, the Sixth Circuit held that the determination of class arbitrability should be presumptively reserved to judicial courts, not arbitrators, unless the arbitration agreement expressly provides otherwise. This Note discusses the circuit split that arose following the Sixth Circuit\u27s holding in Reed Elsevier, and then explores the precedential value of United States Supreme Court plurality opinions. In conclusion, this note argues that Reed Elsevier highlights the jurisprudence of recent Supreme Court cases; together, these cases indicate a shift away from Bazzle3 and are more persuasive than any single plurality opinion

Biological tissue mechanics with fibres modelled as one dimensional Cosserat continua: applications to cardiac tissue in healthy and diseased states

Includes bibliographical references.Classically, the elastic behaviour of cardiac tissue mechanics is modelled using anisotropic strain energy functions capturing the averaged behaviour of its fibrous microstructure. The strain energy function can be derived via representation theorems for anisotropic functions where a suitable nonlinear strain tensor, e.g. the Green strain tensor, describes locally the current state of strain [57, 150, 158]. These kinds of approaches, however, are usually of phenomenological nature and do not elucidate on the complex heterogeneous material composition of cardiac tissue characterized by different fibre hierarchies interwoven by collagen, elastin and coronary capillaries [61, 115]. Thus, pathological changes of microstructural constituents, e.g. with regards to the extra cellular matrix, and their implications on the macroscopically observable material behaviour cannot be directly investigated. In this research the fibrous characteristics of the myocardium are modelled by one dimensional Cosserat continua. This additionally allows for the inclusion of fibre motion relative to the matrix representing the non-local material response due to twisting and bending of fibres. In this sense, a so-called characteristic scaling parameter associated with the micro structure, becomes a material parameters of the formulation. The ability to explicitly account for torsion and bending in the constitutive law gives this approach a natural advantage over classical formulations. Moreover, the additional degrees of freedom in the kinematic description allow for more complex, realistic deformations. The assumed hyperelastic material behaviour of myocardial tissue is represented by a nonlinear strain energy function which includes the contributions linked to the Cosserat fibre continuum and the complementary terms which refer to the extra-cellular matrix. Utilizing the element-free Galerkin method, simulations of the left ventricle undergoing various stages of the cardiac cycle are introduced to investigate ventricular tissue mechanics

Relationship of Transmural Variations in Myofiber Contractility to Left Ventricular Ejection Fraction: Implications for Modeling Heart Failure Phenotype With Preserved Ejection Fraction

The pathophysiological mechanisms underlying preserved left ventricular (LV) ejection fraction (EF) in patients with heart failure and preserved ejection fraction (HFpEF) remain incompletely understood. We hypothesized that transmural variations in myofiber contractility with existence of subendocardial dysfunction and compensatory increased subepicardial contractility may underlie preservation of LVEF in patients with HFpEF. We quantified alterations in myocardial function in a mathematical model of the human LV that is based on the finite element method. The fiber-reinforced material formulation of the myocardium included passive and active properties. The passive material properties were determined such that the diastolic pressure-volume behavior of the LV was similar to that shown in published clinical studies of pressure-volume curves. To examine changes in active properties, we considered six scenarios: (1) normal properties throughout the LV wall; (2) decreased myocardial contractility in the subendocardium; (3) increased myocardial contractility in the subepicardium; (4) myocardial contractility decreased equally in all layers, (5) myocardial contractility decreased in the midmyocardium and subepicardium, (6) myocardial contractility decreased in the subepicardium. Our results indicate that decreased subendocardial contractility reduced LVEF from 53.2 to 40.5%. Increased contractility in the subepicardium recovered LVEF from 40.5 to 53.2%. Decreased contractility transmurally reduced LVEF and could not be recovered if subepicardial and midmyocardial contractility remained depressed. The computational results simulating the effects of transmural alterations in the ventricular tissue replicate the phenotypic patterns of LV dysfunction observed in clinical practice. In particular, data for LVEF, strain and displacement are consistent with previous clinical observations in patients with HFpEF, and substantiate the hypothesis that increased subepicardial contractility may compensate for subendocardial dysfunction and play a vital role in maintaining LVEF

Effect of Contact Force on Pulsed Field Ablation Lesions in Porcine Cardiac Tissue.

BACKGROUND Contact force has been used to titrate lesion formation for radiofrequency ablation. Pulsed Field Ablation (PFA) is a field-based ablation technology for which limited evidence on the impact of contact force on lesion size is available. METHODS Porcine hearts (n=6) were perfused using a modified Langendorff set-up. A prototype focal PFA catheter attached to a force gauge was held perpendicular to the epicardium and lowered until contact was made. Contact force was recorded during each PFA delivery. Matured lesions were cross-sectioned, stained, and the lesion dimensions measured. RESULTS A total of 82 lesions were evaluated with contact forces between 1.3 g and 48.6 g. Mean lesion depth was 4.8 ± 0.9 mm (standard deviation), mean lesion width was 9.1 ± 1.3 mm and mean lesion volume was 217.0. ± 96.6 mm3 . Linear regression curves showed an increase of only 0.01 mm in depth (Depth = 0.01*Contact Force + 4.41, R2 = 0.05), 0.03 mm in width (Width = 0.03*Contact Force + 8.26, R2 = 0.13) for each additional gram of contact force, and 2.20 mm3 in volume (Volume = 2.20*Contact Force + 162, R2 = 0.10). CONCLUSIONS Increasing contact force using a bipolar, biphasic focal PFA system has minimal effects on acute lesion dimensions in an isolated porcine heart model and achieving tissue contact is more important than the force with which that contact is made. This article is protected by copyright. All rights reserved

Relationship of Transmural Variations in Myofiber Contractility to Left Ventricular Ejection Fraction: Implications for Modeling Heart Failure Phenotype With Preserved Ejection Fraction

The pathophysiological mechanisms underlying preserved left ventricular (LV) ejection fraction (EF) in patients with heart failure and preserved ejection fraction (HFpEF) remain incompletely understood. We hypothesized that transmural variations in myofiber contractility with existence of subendocardial dysfunction and compensatory increased subepicardial contractility may underlie preservation of LVEF in patients with HFpEF. We quantified alterations in myocardial function in a mathematical model of the human LV that is based on the finite element method. The fiber-reinforced material formulation of the myocardium included passive and active properties. The passive material properties were determined such that the diastolic pressure-volume behavior of the LV was similar to that shown in published clinical studies of pressure-volume curves. To examine changes in active properties, we considered six scenarios: (1) normal properties throughout the LV wall; (2) decreased myocardial contractility in the subendocardium; (3) increased myocardial contractility in the subepicardium; (4) myocardial contractility decreased equally in all layers, (5) myocardial contractility decreased in the midmyocardium and subepicardium, (6) myocardial contractility decreased in the subepicardium. Our results indicate that decreased subendocardial contractility reduced LVEF from 53.2 to 40.5%. Increased contractility in the subepicardium recovered LVEF from 40.5 to 53.2%. Decreased contractility transmurally reduced LVEF and could not be recovered if subepicardial and midmyocardial contractility remained depressed. The computational results simulating the effects of transmural alterations in the ventricular tissue replicate the phenotypic patterns of LV dysfunction observed in clinical practice. In particular, data for LVEF, strain and displacement are consistent with previous clinical observations in patients with HFpEF, and substantiate the hypothesis that increased subepicardial contractility may compensate for subendocardial dysfunction and play a vital role in maintaining LVEF

The second warning to humanity: contributions and solutions from conservation physiology

In 1992, the Union of Concerned Scientists shared their ‘World Scientists’ Warning to Humanity’ with governmental leaders worldwide, calling for immediate action to halt the environmental degradation that threatens the systems that support life on Earth. A follow-up ‘Second Warning’ was released in 2017, with over 15 000 scientists as signatories, describing the lack of progress in adopting the sustainable practices necessary to safeguard the biosphere. In their ‘Second Warning’, Ripple and colleagues provided 13 ‘diverse and effective steps humanity can take to transition to sustainability.’ Here, we discuss how the field of conservation physiology can contribute to six of these goals: (i) prioritizing connected, well-managed reserves; (ii) halting the conversion of native habitats to maintain ecosystem services; (iii) restoring native plant communities; (iv) rewilding regions with native species; (v) developing policy instruments; and (vi) increasing outdoor education, societal engagement and reverence for nature. Throughout, we focus our recommendations on specific aspects of physiological function while acknowledging that the exact traits that will be useful in each context are often still being determined and refined. However, for each goal, we include a short case study to illustrate a specific physiological trait or group of traits that is already being utilized in that context. We conclude with suggestions for how conservation physiologists can broaden the impact of their science aimed at accomplishing the goals of the ‘Second Warning’. Overall, we provide an overview of how conservation physiology can contribute to addressing the grand socio-environmental challenges of our time

Influence of packing density and stress on the dynamic response of granular materials

Laboratory geophysics tests including bender elements and acoustic emission measure the speed of propagation of stress or sound waves in granular materials to derive elastic stiffness parameters. This contribution builds on earlier studies to assess whether the received signal characteristics can provide additional information about either the material’s behaviour or the nature of the material itself. Specifically it considers the maximum frequency that the material can transmit; it also assesses whether there is a simple link between the spectrum of the received signal and the natural frequencies of the sample. Discrete element method (DEM) simulations of planar compression wave propagation were performed to generate the data for the study. Restricting consideration to uniform (monodisperse) spheres, the material fabric was varied by considering face-centred cubic lattice packings as well as random configurations with different packing densities. Supplemental analyses, in addition to the DEM simulations, were used to develop a more comprehensive understanding of the system dynamics. The assembly stiffness and mass matrices were extracted from the DEM model and these data were used in an eigenmode analysis that provided significant insight into the observed overall dynamic response. The close agreement of the wave velocities estimated using eigenmode analysis with the DEM results confirms that DEM wave propagation simulations can reliably be used to extract material stiffness data. The data show that increasing either stress or density allows higher frequencies to propagate through the media, but the low-pass wavelength is a function of packing density rather than stress level. Prior research which had hypothesised that there is a simple link between the spectrum of the received signal and the natural sample frequencies was not substantiated

An aging Interventions Testing Program: study design and interim report

The National Institute on Aging's Interventions Testing Program (ITP) has developed a plan to evaluate agents that are considered plausible candidates for delaying rates of aging. Key features include: (i) use of genetically heterogeneous mice (a standardized four-way cross), (ii) replication at three test sites (the Jackson Laboratory, TJL; University of Michigan, UM; and University of Texas, UT), (iii) sufficient statistical power to detect 10 changes in lifespan, (iv) tests for age-dependent changes in T cell subsets and physical activity, and (v) an annual solicitation for collaborators who wish to suggest new interventions for evaluation. Mice in the first cohort were exposed to one of four agents: aspirin, nitroflurbiprofen (NFP), 4-OH- -phenyl-N-tert-butyl nitrone (4-OH-PBN), or nordihydroguiaretic acid (NDGA). An interim analysis was conducted using survival data available on the date at which at least 50 of the male control mice had died at each test site. Survival of control males was significantly higher, at the interim time-point, at UM than at UT or TJL; all three sites had similar survival of control females. Males in the NDGA group had significantly improved survival ( P 0.0004), with significant effects noted at TJL ( P < 0.01) and UT ( P < 0.04). None of the other agents altered survival, although there was a suggestion ( P 0.07) of a beneficial effect of aspirin in males. More data will be needed to determine if any of these compounds can extend maximal lifespan, but the current data show that NDGA reduces early life mortality risks in genetically heterogeneous mice at multiple test sites.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74625/1/j.1474-9726.2007.00311.x.pd