Rigorous Multicomponent Reactive Separations Modelling : Complete Consideration of Reaction-Diffusion Phenomena

This paper gives the first step of the development of a rigorous multicomponent reactive separation model. Such a model is highly essential to further the optimization of acid gases removal plants (CO2 capture, gas treating, etc.) in terms of size and energy consumption, since chemical solvents are conventionally used.Firstly, two main modelling approaches are presented: the equilibrium-based and the rate-based approaches. Secondly, an extended rate-based model with rigorous modelling methodology for diffusion-reaction phenomena is proposed. The film theory and the generalized Maxwell-Stefan equations are used in order to characterize multicomponent interactions. The complete chain of chemical reactions is taken into account. The reactions can be kinetically controlled or at chemical equilibrium, and they are considered for both liquid film and liquid bulk. Thirdly, the method of numerical resolution is described. Coupling the generalized Maxwell-Stefan equations with chemical equilibrium equations leads to a highly non-linear Differential-Algebraic Equations system known as DAE index 3. The set of equations is discretized with finite-differences as its integration by Gear method is complex. The resulting algebraic system is resolved by the Newton- Raphson method. Finally, the present model and the associated methods of numerical resolution are validated for the example of esterification of methanol. This archetype non-electrolytic system permits an interesting analysis of reaction impact on mass transfer, especially near the phase interface. The numerical resolution of the model by Newton-Raphson method gives good results in terms of calculation time and convergence. The simulations show that the impact of reactions at chemical equilibrium and that of kinetically controlled reactions with high kinetics on mass transfer is relatively similar. Moreover, the Fick’s law is less adapted for multicomponent mixtures where some abnormalities such as counter-diffusion take place

How uncertainty enables non-classical dynamics

The uncertainty principle limits quantum states such that when one observable takes predictable values there must be some other mutually unbiased observables which take uniformly random values. We show that this restrictive condition plays a positive role as the enabler of non-classical dynamics in an interferometer. First we note that instantaneous action at a distance between different paths of an interferometer should not be possible. We show that for general probabilistic theories this heavily curtails the non-classical dynamics. We prove that there is a trade-off with the uncertainty principle, that allows theories to evade this restriction. On one extreme, non-classical theories with maximal certainty have their non-classical dynamics absolutely restricted to only the identity operation. On the other extreme, quantum theory minimises certainty in return for maximal non-classical dynamics.Comment: 4 pages + 4 page technical supplement, 2 figure

Exhaled metabolite patterns to identify recent asthma exacerbations

Asthma is a chronic respiratory disease that can lead to exacerbations, defined as acute episodes of worsening respiratory symptoms and lung function. Predicting the occurrence of these exacerbations is an important goal in asthma management. The measurement of exhaled breath by electronic nose (eNose) may allow for the monitoring of clinically unstable asthma and exacerbations. However, data on its ability to perform this is lacking. We aimed to evaluate whether eNose could identify patients that recently had asthma exacerbations. We performed a cross-sectional study, measuring exhaled breath using the SpiroNose in adults with a physician-reported diagnosis of asthma. Patients were randomly divided into a training (n = 252) and validation (n = 109) set. For the analysis of eNose signals, principal component (PC) and linear discriminant analysis (LDA) were performed. LDA, based on PC1-4, reliably discriminated between patients who had a recent exacerbation from those who had not (training receiver operating characteristic (ROC)–area under the curve (AUC) = 0.76,95% CI 0.69–0.82), (validation AUC = 0.76, 95% CI 0.64–0.87). Our study showed that, exhaled breath analysis using eNose could accurately identify asthma patients who recently had an exacerbation, and could indicate that asthma exacerbations have a specific exhaled breath pattern detectable by eNose

Beyond the ‘Tomlinson Trap’: analysing the effectiveness of section 1 of the Compensation Act 2006

One of the intentions underpinning section 1 of the Compensation Act 2006 was to provide reassurance to individual volunteers, and voluntary organisations, involved in what the provision called ‘desirable activities’ and including sport. The perception was that such volunteers, motivated by an apprehension about their increased vulnerability to negligence liability, and as driven by a fear of a wider societal compensation culture, were engaging excessively in risk-averse behaviour to the detriment of such socially desirable activities. Academic commentary on section 1 of the Compensation Act 2006 has largely regarded the provision as unnecessary and doing little more than restating existing common law practice. This article argues otherwise and, on critically reviewing the emerging jurisprudence, posits the alternative view that section 1, in practice, affords an enhanced level of protection and safeguarding for individuals undertaking functions in connection with a desirable activity. Nonetheless, the occasionally idiosyncratic judicial interpretation given to term ‘desirable activity’, potentially compounded by recent enactment of the Social Action, Responsibility and Heroism Act 2015, remains problematic. Two points of interest will be used to inform this debate. First, an analysis of the then House of Lords’ decision in Tomlinson and its celebrated ‘balancing exercise’ when assessing reasonableness in the context of negligence liability. Second, a fuller analysis of the application of section 1 in the specific context of negligence actions relating to the coaching of sport where it is argued that the, albeit limited, jurisprudence might support the practical utility of a heightened evidential threshold of gross negligence

Activity and Process Stability of Purified Green Pepper (Capsicum annuum) Pectin Methylesterase

Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 °C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 °C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55?57 °C) and a biphasic model for higher temperatures (58?70 °C). The enzyme showed a stable behavior toward high-pressure/temperature treatments. Keywords: Capsicum annuum; pepper; pectin methylesterase; purification; characterization; thermal and high-pressure stabilit

Tomo-seq identifies SOX9 as a key regulator of cardiac fibrosis during ischemic injury

Background: Cardiac ischemic injury induces a pathological remodeling response, which can ultimately lead to heart failure. Detailed mechanistic insights into molecular signaling pathways relevant for different aspects of cardiac remodeling will support the identification of novel therapeutic targets. Methods: While genome-wide transcriptome analysis on diseased tissues has greatly advanced our understanding of the regulatory networks that drive pathological changes in the heart, this approach has been disadvantaged by the fact that the signals are derived from tissue homogenates. Here we used tomo-seq to obtain a genome-wide gene expression signature with high spatial resolution spanning from the infarcted area to the remote to identify new regulators of cardiac remodeling. Cardiac tissue samples from patients suffering from ischemic heart disease were used to validate our findings. Results: Tracing transcriptional differences with a high spatial resolution across the infarcted heart enabled us to identify gene clusters that share a comparable expression profile. The spatial distribution patterns indicated a separation of expressional changes for genes involved in specific aspects of cardiac remodeling, like fibrosis, cardiomyocyte hypertrophy, and calcium-handling (Col1a2, Nppa, and Serca2). Subsequent correlation analysis allowed for the identification of novel factors that share a comparable transcriptional regulation pattern across the infarcted tissue. The strong correlation between the expression levels of these known marker genes and the expression of the co-regulated genes could be confirmed in human ischemic cardiac tissue samples. Follow-up analysis identified SOX9 as common transcriptional regulator of a large portion of the fibrosis-related genes that become activated under conditions of ischemic injury. Lineage-tracing experiments indicated the majority of COL1-positive fibroblasts to stem from a pool of SOX9-expressing cells and in vivo loss of Sox9 blunted the cardiac fibrotic response upon ischemic injury. The co-localization between SOX9 and COL1 could also be confirmed in patients suffering from ischemic heart disease. Conclusions: Based on the exact local expression cues, tomo-seq can serve to reveal novel genes and key transcription factors involved in specific aspects of cardiac remodeling. Using tomo-seq we were able to unveil the unknown relevance of SOX9 as key regulator of cardiac fibrosis, pointing to SOX9 as potential therapeutic target for cardiac fibrosis

Introducing an Ethics Framework for health priority-setting in South Africa on the path to universal health coverage

Background. South Africa (SA) has embarked on a process to implement universal health coverage (UHC) funded by National Health Insurance (NHI). The 2019 NHI Bill proposes creation of a health technology assessment (HTA) body to inform decisions about which interventions NHI funds will cover under UHC. In practice, HTA often relies mainly on economic evaluations of cost-effectiveness and budget impact, with less attention to the systematic, specific consideration of important social, organisational and ethical impacts of the health technology in question. In this context, the South African Values and Ethics for Universal Health Coverage (SAVE-UHC) research project recognised an opportunity to help shape the health priority-setting process by providing a way to take account of multiple, ethically relevant considerations that reflect SA values. The SAVE-UHC Research Team developed and tested an SA-specific Ethics Framework for HTA assessment and analysis.Objectives. To develop and test an Ethics Framework for use in the SA context for health priority-setting.Methods. The Framework was developed iteratively by the authors and a multidisciplinary panel (18 participants) over a period of 18 months, using the principles outlined in the 2015 NHI White Paper as a starting point. The provisional Ethics Framework was then tested with multi-stakeholder simulated appraisal committees (SACs) in three provinces. The membership of each SAC roughly reflected the composition of a potential SA HTA committee. The deliberations and dedicated focus group discussions after each SAC meeting were recorded, analysed and used to refine the Framework, which was presented to the Working Group for review, comment and final approval.Results. This article describes the 12 domains of the Framework. The first four (Burden of the Health Condition, Expected Health Benefits and Harms, Cost-Effectiveness Analysis, and Budget Impact) are commonly used in HTA assessments, and a further eight cover the other ethical domains. These are Equity, Respect and Dignity, Impacts on Personal Financial Situation, Forming and Maintaining Important Personal Relationships, Ease of Suffering, Impact on Safety and Security, Solidarity and Social Cohesion, and Systems Factors and Constraints. In each domain are questions and prompts to enable use of the Framework by both analysts and assessors. Issues that arose, such as weighting of the domains and the availability of SA evidence, were discussed by the SACs.Conclusions. The Ethics Framework is intended for use in priority-setting within an HTA process. The Framework was well accepted by a diverse group of stakeholders. The final version will be a useful tool not only for HTA and other priority-setting processes in SA, but also for future efforts to create HTA methods in SA and elsewhere

Collective phase description of globally coupled excitable elements

We develop a theory of collective phase description for globally coupled noisy excitable elements exhibiting macroscopic oscillations. Collective phase equations describing macroscopic rhythms of the system are derived from Langevin-type equations of globally coupled active rotators via a nonlinear Fokker-Planck equation. The theory is an extension of the conventional phase reduction method for ordinary limit cycles to limit-cycle solutions in infinite-dimensional dynamical systems, such as the time-periodic solutions to nonlinear Fokker-Planck equations representing macroscopic rhythms. We demonstrate that the type of the collective phase sensitivity function near the onset of collective oscillations crucially depends on the type of the bifurcation, namely, it is type-I for the saddle-node bifurcation and type-II for the Hopf bifurcation.Comment: 18 pages, 6 figure