Analysis of Lithium‐Ion Battery State and Degradation via Physicochemical Cell and SEI Modeling

The quality of lithium-ion batteries is affected by the formation of the solid electrolyte interphase (SEI). For a better understanding of its effect on cell performance and aging, fast and economically scalable SEI diagnostics are indispensable. Battery models promise to extract hardly accessible interfacial and bulk properties of the SEI from electrochemical impedance spectra and discharge data. The common analysis of only one measurement, often with empirical models, impedes a precise localization of degradation-related and performance-limiting processes. This work offers a solution by combining physicochemical SEI and cell modeling for the joint analysis of both measurement types. Our analysis highlights the minor importance of the SEI ionic conductivity for cell performance along with a significant improvement and notable effect of its interfacial properties along aging. Such a detailed understanding of the initial SEI and its evolution over time could enable, e. g., a knowledge-based optimization of the cell formation process

Energy Landscapes of Deoxyxylo- and Xylo-Nucleic Acid Octamers.

Artificial analogues of the natural nucleic acids have attracted interest as a diverse class of information storage molecules capable of self-replication. In this study, we use the computational potential energy landscape framework to investigate the structural and dynamical properties of xylo- and deoxyxylo-nucleic acids (XyNA and dXyNA), which are derived from their respective RNA and DNA analogues by inversion of a single chiral center in the sugar moiety of the nucleotides. For an octameric XyNA sequence and the analogue dXyNA, we observe facile conformational transitions between a left-handed helix, which is the free energy global minimum, and a ladder-type structure with approximately zero helicity. The competing ensembles are better separated in the dXyNA, making it a more suitable candidate for a molecular switch, whereas the XyNA exhibits additional flexibility. Both energy landscapes exhibit greater frustration than we observe in RNA or DNA, in agreement with the higher degree of optimization expected from the principle of minimal frustration in evolved biomolecules

Influence of preoperative leg pain and radiculopathy on outcomes in mono-segmental lumbar total disc replacement: results from a nationwide registry

Purpose: Currently, many pre-conditions are regarded as relative or absolute contraindications for lumbar total disc replacement (TDR). Radiculopathy is one among them. In Switzerland it is left to the surgeon's discretion when to operate if he adheres to a list of pre-defined indications. Contraindications, however, are less clearly specified. We hypothesized that, the extent of pre-operative radiculopathy results in different benefits for patients treated with mono-segmental lumbar TDR. We used patient perceived leg pain and its correlation with physician recorded radiculopathy for creating the patient groups to be compared. Methods: The present study is based on the dataset of SWISSspine, a government mandated health technology assessment registry. Between March 2005 and April 2009, 577 patients underwent either mono- or bi-segmental lumbar TDR, which was documented in a prospective observational multicenter mode. A total of 416 cases with a mono-segmental procedure were included in the study. The data collection consisted of pre-operative and follow-up data (physician based) and clinical outcomes (NASS form, EQ-5D). A receiver operating characteristic (ROC) analysis was conducted with patients' self-indicated leg pain and the surgeon-based diagnosis "radiculopathy”, as marked on the case report forms. As a result, patients were divided into two groups according to the severity of leg pain. The two groups were compared with regard to the pre-operative patient characteristics and pre- and post-operative pain on Visual Analogue Scale (VAS) and quality of life using general linear modeling. Results: The optimal ROC model revealed a leg pain threshold of 40≤VAS>40 for the absence or the presence of "radiculopathy”. Demographics in the resulting two groups were well comparable. Applying this threshold, the mean pre-operative leg pain level was 16.5 points in group 1 and 68.1 points in group 2 (p<0.001). Back pain levels differed less with 63.6 points in group 1 and 72.6 in group 2 (p<0.001). Pre-operative quality of life showed considerable differences with an 0.44 EQ-5D score in group 1 and 0.29 in group 2 (p<0.001, possible score range −0.6 to 1). At a mean follow-up time of 8 months, group 1 showed a mean leg pain improvement of 3.6 points and group 2 of 41.1 points (p<0.001). Back pain relief was 35.6 and 39.1 points, respectively (p=0.27). EQ-5D score improvement was 0.27 in group 1 and 0.41 in group 2 (p=0.11). Conclusions: Patients labeled as having radiculopathy (group 2) do mostly have pre-operative leg pain levels≥40. Applying this threshold, the patients with pre-operative leg pain do also have more severe back pain and a considerably lower quality of life. Their net benefit from the lumbar TDR is higher and they do have similar post-operative back and leg pain levels as well as the quality of life as patients without pre-operative leg pain. Although randomized controlled trials are required to confirm these findings, they put leg pain and radiculopathy into perspective as absolute contraindications for TD

Integrated Analysis of Commuters’ Energy Consumption

There are strong interactions between energy consumption at home, in the office, and in the traffic system. For example, workers can telecommute, saving the energy at the office and in the transport system, but on the other hand increasing energy consumption at home. As an alternative measure, making working hours less flexible and thus forcing everybody to be at the workplace at the same time reduces the energy consumption of the office building. Both measures in addition have traffic congestion consequences. This paper discusses these policies based on a simple analytical model as well as based on a simulation model which includes a sophisticated simulation of the transport system

The role of SGLT1 and GLUT2 in intestinal glucose transport and sensing.

Intestinal glucose absorption is mediated by SGLT1 whereas GLUT2 is considered to provide basolateral exit. Recently, it was proposed that GLUT2 can be recruited into the apical membrane after a high luminal glucose bolus allowing bulk absorption of glucose by facilitated diffusion. Moreover, SGLT1 and GLUT2 are suggested to play an important role in intestinal glucose sensing and incretin secretion. In mice that lack either SGLT1 or GLUT2 we re-assessed the role of these transporters in intestinal glucose uptake after radiotracer glucose gavage and performed Western blot analysis for transporter abundance in apical membrane fractions in a comparative approach. Moreover, we examined the contribution of these transporters to glucose-induced changes in plasma GIP, GLP-1 and insulin levels. In mice lacking SGLT1, tissue retention of tracer glucose was drastically reduced throughout the entire small intestine whereas GLUT2-deficient animals exhibited higher tracer contents in tissue samples than wild type animals. Deletion of SGLT1 resulted also in reduced blood glucose elevations and abolished GIP and GLP-1 secretion in response to glucose. In mice lacking GLUT2, glucose-induced insulin but not incretin secretion was impaired. Western blot analysis revealed unchanged protein levels of SGLT1 after glucose gavage. GLUT2 detected in apical membrane fractions mainly resulted from contamination with basolateral membranes but did not change in density after glucose administration. SGLT1 is unequivocally the prime intestinal glucose transporter even at high luminal glucose concentrations. Moreover, SGLT1 mediates glucose-induced incretin secretion. Our studies do not provide evidence for GLUT2 playing any role in either apical glucose influx or incretin secretion

Myth and Reality of a Universal Lithium-Ion Battery Electrode Design Optimum: A Perspective and Case Study

The quest toward optimal electrode design for energy‐ and power‐demanding applications involves besides experimental effort also less resource‐intensive model‐based studies. The diversity of optimization objectives and benchmark systems complicates the practical utilization of available methods and gained knowledge. Despite the increasing importance of fast charging, electrode design studies commonly focus only on discharge characteristics. This paper features, besides an overview and perspective of electrode structuring concepts and optimization pathways, a model‐based full cell parameter screening of two‐layered electrodes for charge and discharge. The small fraction of cells with superior performance among the evaluated configurations underlines the importance of a joint experimental and model‐based electrode design optimization. The results further indicate that the performance of cell designs tailored for fast charge or fast discharge differs substantially; the gap widens if charging is terminated below 0 V versus Li/Li+ to prevent lithium plating. The broad parameter screening is complemented by a high‐resolution half cell parameter study. Their comparison underlines that the benefit of electrode structuring depends heavily on the study extent and the chosen benchmark. Furthermore, the importance of the parameter space surrounding an optimal electrode design for production with process tolerances is highlighted

Designing biomass policy: the political economy of renewable energy for net zero

The climate, ecological, and energy crises require change in our political, economic, and societal systems to ensure we decouple humanity from a reliance on fossil fuels, prevent rising carbon dioxide emissions, and develop sustainable solutions for people and the planet. As well as technical processes, renewable energy transitions are processes of social, environmental, and economic change which have the potential to challenge the status quo. This status quo determines who benefits from energy, where wealth is created, and the level of inequality between stakeholders within our energy systems. The politicization of energy transitions motivates stakeholders to engage in the policymaking process to ensure any trade-offs associated with policy changes benefit them. Bioenergy is unique amongst renewable energy sources as it is inherently linked to biomass extraction from our natural environment and because biomass is the only source of renewable carbon. However, this further politicizes its use and is a source of controversy in public debate. Polarized perspectives in the public debate on biomass policy allow stakeholders to assert themselves as experts on the topic and to make authoritative claims that further their interests to influence policy development. Therefore, political and economic drivers shape and influence the sustainability and success of proposed policies. Despite this, there is little research into the nontechnical factors influencing the design of sustainable biomass policy for net zero. This research highlights how political economy impacts the success of renewable energy technologies in replacing fossil fuels and the implications for using bioenergy

Towards a simulation of minibuses in South Africa

After private cars, minibus taxis are the most common transport mode in South Africa. Especially for low-income citizens living in townships, minibus services are often the only possibility for mobility. Despite the great importance of the mode, there is very little knowledge of routes, fares, and the number of minibuses. Hence, it is difficult to simulate and to understand the influence of this mode on other modes and on transport planning in general.. is article presents the development of the first "close-to-reality" minibus supply model based on demand and street network only The approach adopts the survival-of-the-fittest principle, using a co-evolutionary algorithm that is integrated into a microscopic multi-agent simulation framework The successful application of the approach to a large-scale, real-world scenario in the Nelson Mandela Bay Area Municipality in South Africa shows that it is able to identify the main minibus corridors as well as to find robust service coverage in lower-demand areas The resulting minibus supply model can then be used for planning purposes (e.g., to investigate aspects of strategic, operational, or regulatory changes)