Solid oxide fuel cells (SOFC) have emerged as energy conversion devices in achieving high efficiency of over 70% with regeneration. The critical components of SOFC include anode, electrolyte, and ...cathode. However, for a stack of individual SOFCs, the evaluation of sealants and interconnects are also essential. In this review article, material selection, fundamentals of operation and underlying mechanisms, processing, microstructural and phase characterization, and the functionality and performance of individual SOFC components are presented in detail. The major challenges and complexity in functional section of SOFC include: (i) poisoning via sulfur and coke deposition, surface diffusion of adsorbate, and charge transfer at triple-phase boundary (TPB) in anode, (ii) hindered O2- migration that converts chemical energy into electrical energy in the solid electrolyte (thus, the creation of ion transfer channels, ease of O2- migration, dissociation of vacancy around dopants, straining of lattice, and other factors such as control of phase and its distribution, grain and grain boundary conductivity, become critical in designing the electrolytes for SOFCs), (iii) multiple rate determining factors such as geometry of active surfaces, and existence of overpotential, in cathode (thereby, comprehensive electrochemical impedance spectroscopy is required for the analysis of solid cathodes in SOFC), (iv) chemical incompatibility and instability in both oxidizing and reducing environments while matching the coefficient of thermal expansion (CTE) in the interconnects in order to sustain large number of thermal cycling during the operation of SOFC, and (v) isolation of the fuel and oxidizing gases while matching the CTE of the anode, cathode and interconnects, using sealant. Moreover, the glass-transition of sealant dictates the maximum allowable working temperature of SOFC. Thus, the necessitated temporal progress in material selection along with a detailed insight into the conceptual role of thermodynamics and kinetics of surface/cell reactions, effect of phases and microstructure on conductivity, fuel flexibility and deterioration in performance of individual fuel cell components, and evolution of new materials are coherently presented. This article provides a comprehensive review with respect to the structure, chemistry, design and selection of materials, underlying mechanisms, and performance of each SOFC component, and it opens up the future directions towards pursuing SOFC research.
Development of high capacity anode materials is one of the essential strategies for next-generation high-performance Li/Na-ion batteries. Rational design, using density functional theory, can ...expedite the discovery of these anode materials. Here, we propose a new anode material, germanium carbide, g-GeC, for Li/Na-ion batteries. Our results show that g-GeC possesses both benefits of the high stability of graphene and the strong interaction between Li/Na and germanene. The single-layer germanium carbide, g-GeC, can be lithiated/sodiated on both sides yielding Li2GeC and Na2GeC with a storage capacity as high as 633 mA h/g. Besides germagraphene's 2D honeycomb structure, fast charge transfer, and high (Li/Na)-ion diffusion and negligible volume change further enhance the anode performance. These findings provide valuable insights into the electronic characteristics of newly predicted 2D g-GeC nanomaterial as a promising anode for (Li/Na)-ion batteries.
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•Germagraphene is designed as anode materials for Li/Na-ion batteries.•Thermodynamics and kinetics of g-GeC as an anode is explored by DFT calculations.•The Li/Na-intercalation into g-GeC can offer a theoretical capacity of 633 mA h/g.•New rational design of Ge/C compounds as novel anode materials is reported.
National and global recommendations for BMI cutoffs to trigger action to prevent obesity-related complications like type 2 diabetes among non-White populations are questionable. We aimed to ...prospectively identify ethnicity-specific BMI cutoffs for obesity based on the risk of type 2 diabetes that are risk-equivalent to the BMI cutoff for obesity among White populations (≥30 kg/m2).
In this population-based cohort study, we used electronic health records across primary care (Clinical Practice Research Datalink) linked to secondary care records (Hospital Episodes Statistics) from a network of general practitioner practices in England. Eligible participants were aged 18 years or older, without any past or current diagnosis of type 2 diabetes, had a BMI of 15·0–50·0 kg/m2 and complete ethnicity data, were registered with a general practitioner practice in England at any point between Sept 1, 1990, and Dec 1, 2018, and had at least 1 year of follow-up data. Patients with type 2 diabetes were identified by use of a CALIBER phenotyping algorithm. Self-reported ethnicity was collapsed into five main categories. Age-adjusted and sex-adjusted negative binomial regression models, with fractional polynomials for BMI, were fitted with incident type 2 diabetes and ethnicity data.
1 472 819 people were included in our study, of whom 1 333 816 (90·6%) were White, 75 956 (5·2%) were south Asian, 49 349 (3·4%) were Black, 10 934 (0·7%) were Chinese, and 2764 (0·2%) were Arab. After a median follow-up of 6·5 years (IQR 3·2–11·2), 97 823 (6·6%) of 1 472 819 individuals were diagnosed with type 2 diabetes. For the equivalent age-adjusted and sex-adjusted incidence of type 2 diabetes at a BMI of 30·0 kg/m2 in White populations, the BMI cutoffs were 23·9 kg/m2 (95% CI 23·6–24·0) in south Asian populations, 28·1 kg/m2 (28·0–28·4) in Black populations, 26·9 kg/m2 (26·7–27·2) in Chinese populations, and 26·6 kg/m2 (26·5–27·0) in Arab populations.
Revisions of ethnicity-specific BMI cutoffs are needed to ensure that minority ethnic populations are provided with appropriate clinical surveillance to optimise the prevention, early diagnosis, and timely management of type 2 diabetes.
National Institute for Health Research.
Obesity and ethnicity are known risk factors for COVID-19 outcomes, but their combination has not been extensively examined. We investigate the association between body mass index (BMI) and COVID-19 ...mortality across different ethnic groups using linked national Census, electronic health records and mortality data for adults in England from the start of pandemic (January 2020) to December 2020. There were 30,067 (0.27%), 1,208 (0.29%), 1,831 (0.29%), 845 (0.18%) COVID-19 deaths in white, Black, South Asian and other ethnic minority groups, respectively. Here we show that BMI was more strongly associated with COVID-19 mortality in ethnic minority groups, resulting in an ethnic risk of COVID-19 mortality that was dependant on BMI. The estimated risk of COVID-19 mortality at a BMI of 40 kg/m
in white ethnicities was equivalent to the risk observed at a BMI of 30.1 kg/m
, 27.0 kg/m
, and 32.2 kg/m
in Black, South Asian and other ethnic minority groups, respectively.
Atrial fibrillation： the current epidemic Morillo, Carlos A; Banerjee, Amitava; Perel, Pablo ...
Journal of geriatric cardiology : JGC,
03/2017, Letnik:
14, Številka:
3
Journal Article
Odprti dostop
Atrial fibrillation （AF） is the most common arrhythmia diagnosed in clinical practice. The consequences of AF have been clearly estab- lished in multiple large observational cohort studies and ...include increased stroke and systemic embolism rates if no oral anticoagulation is prescribed, with increased morbidity and mortality. With the worldwide aging of the population characterized by a large influx of ＂baby boomers＂ with or without risk factors for developing AF, an epidemic is forecasted within the next 10 to 20 years. Although not all studies support this evidence, it is clear that AF is on the rise and a significant amount of health resources are invested in detecting and managing AF This review focuses on the worldwide burden of AF and reviews global health strategies focused on improving detection, prevention and risk stratification of AF, recently recommended by the World Heart Federation.
New Findings
What is the topic of this review?
The emerging condition of long COVID, its epidemiology, pathophysiological impacts on patients of different backgrounds, physiological mechanisms ...emerging as explanations of the condition, and treatment strategies being trialled. The review leads from a Physiological Society online conference on this topic.
What advances does it highlight?
Progress in understanding the pathophysiology and cellular mechanisms underlying Long COVID and potential therapeutic and management strategies.
Long COVID, the prolonged illness and fatigue suffered by a small proportion of those infected with SARS‐CoV‐2, is placing an increasing burden on individuals and society. A Physiological Society virtual meeting in February 2022 brought clinicians and researchers together to discuss the current understanding of long COVID mechanisms, risk factors and recovery. This review highlights the themes arising from that meeting. It considers the nature of long COVID, exploring its links with other post‐viral illnesses such as myalgic encephalomyelitis/chronic fatigue syndrome, and highlights how long COVID research can help us better support those suffering from all post‐viral syndromes. Long COVID research started particularly swiftly in populations routinely monitoring their physical performance – namely the military and elite athletes. The review highlights how the high degree of diagnosis, intervention and monitoring of success in these active populations can suggest management strategies for the wider population. We then consider how a key component of performance monitoring in active populations, cardiopulmonary exercise training, has revealed long COVID‐related changes in physiology – including alterations in peripheral muscle function, ventilatory inefficiency and autonomic dysfunction. The nature and impact of dysautonomia are further discussed in relation to postural orthostatic tachycardia syndrome, fatigue and treatment strategies that aim to combat sympathetic overactivation by stimulating the vagus nerve. We then interrogate the mechanisms that underlie long COVID symptoms, with a focus on impaired oxygen delivery due to micro‐clotting and disruption of cellular energy metabolism, before considering treatment strategies that indirectly or directly tackle these mechanisms. These include remote inspiratory muscle training and integrated care pathways that combine rehabilitation and drug interventions with research into long COVID healthcare access across different populations. Overall, this review showcases how physiological research reveals the changes that occur in long COVID and how different therapeutic strategies are being developed and tested to combat this condition.
ObjectivesTo estimate the impact of the COVID-19 pandemic on cancer care services and overall (direct and indirect) excess deaths in people with cancer.MethodsWe employed near real-time weekly data ...on cancer care to determine the adverse effect of the pandemic on cancer services. We also used these data, together with national death registrations until June 2020 to model deaths, in excess of background (pre-COVID-19) mortality, in people with cancer. Background mortality risks for 24 cancers with and without COVID-19-relevant comorbidities were obtained from population-based primary care cohort (Clinical Practice Research Datalink) on 3 862 012 adults in England.ResultsDeclines in urgent referrals (median=−70.4%) and chemotherapy attendances (median=−41.5%) to a nadir (lowest point) in the pandemic were observed. By 31 May, these declines have only partially recovered; urgent referrals (median=−44.5%) and chemotherapy attendances (median=−31.2%). There were short-term excess death registrations for cancer (without COVID-19), with peak relative risk (RR) of 1.17 at week ending on 3 April. The peak RR for all-cause deaths was 2.1 from week ending on 17 April. Based on these findings and recent literature, we modelled 40% and 80% of cancer patients being affected by the pandemic in the long-term. At 40% affected, we estimated 1-year total (direct and indirect) excess deaths in people with cancer as between 7165 and 17 910, using RRs of 1.2 and 1.5, respectively, where 78% of excess deaths occured in patients with ≥1 comorbidity.ConclusionsDramatic reductions were detected in the demand for, and supply of, cancer services which have not fully recovered with lockdown easing. These may contribute, over a 1-year time horizon, to substantial excess mortality among people with cancer and multimorbidity. It is urgent to understand how the recovery of general practitioner, oncology and other hospital services might best mitigate these long-term excess mortality risks.
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