Spectroscopic studies of excited states in polyfluorene:small molecule blend films

In organic solar cells, understanding of interfacial processes and energy losses governing device performance is crucial to the development of new organic photovoltaic materials. This thesis reports on spectroscopic studies addressing the conditions for interfacial excited-state losses in donor-acceptor organic blends based on polyfluorene copolymers. The first chapter of results addresses the process of energy transfer in polyfluorene:fullerene blends. Novel fullerene materials based upon multiply substituted C60 and C70 are used in order to modify the energy levels, packing and photophysics in the blend. In these blends, a limitation becomes apparent in that an increase in the offset between the donor ionisation potential and the acceptor electron affinity (expected to increase the open circuit voltage) is accompanied by a loss in photocurrent and the formation of fullerene singlet and triplet states, above a threshold offset of 1.6 electronvolts. Spectroscopic measurements support a mechanism of resonant energy transfer from polymer to fullerene as a process leading to significant energy loss. In these polymers, the efficiency of hole transfer relative to fullerene intersystem crossing influences charge generation yield. The second chapter of results addresses charge transfer ('exciplex') emission as an important source of information about the photophysics of organic-organic interfaces. Blends of emissive polyfluorenes with n-type silole derivatives exhibit charge transfer emission from an interfacial state. The decrease in oscillator strength of the exciplex emission with exciplex energy is assigned to an increase in charge transfer character, explained either by the presence of electron withdrawing moieties, or an increase in solid-state ordering. The third results chapter presents a photophysical study of a silicon-bridged polyindenofluorene polymer blended with the fullerene PCBM. In this system the lifetime of the polymer triplet displays a dependence upon PCBM content in the film, indicating that the polymer triplet dynamics are influenced by interfacial processes

de Sitter Galileon

We generalize the Galileon symmetry and its relativistic extension to a de Sitter background. This is made possible by studying a probe-brane in a flat five-dimensional bulk using a de Sitter slicing. The generalized Lovelock invariants induced on the probe brane enjoy the induced Poincar\'e symmetry inherited from the bulk, while living on a de Sitter geometry. The non-relativistic limit of these invariants naturally maintain a generalized Galileon symmetry around de Sitter while being free of ghost-like pathologies. We comment briefly on the cosmology of these models and the extension to the AdS symmetry as well as generic FRW backgrounds

Cost and cost-effectiveness analysis of mass drug administration compared to school-based targeted preventive chemotherapy for hookworm control in Dak Lak province, Vietnam

Background: School-based targeted preventive chemotherapy (PC), the main strategy for soil-transmitted helminths (STH) control, excludes other at-risk populations including adults and preschool children. Mass drug administration (MDA), covering all age groups, would bring additional health benefits but also requires greater investment. This cost survey and cost-effectiveness analysis compared MDA with school-based targeted PC for STH control in Dak Lak, Vietnam, where STH are endemic. Methods: A cost survey was conducted in 2020 to estimate the total and per person economic and financial cost of each strategy. Monte Carlo simulation accounted for uncertainty in cost estimates. The primary effectiveness measure was hookworm-related disability-adjusted life years (DALYs) averted, and secondary measures were hookworm infection-years averted and moderate-to-heavy intensity hookworm infection-years averted. A Markov model was used to determine the incremental cost-effectiveness ratio (ICER) of MDA compared to school-based targeted PC using a government payer perspective and a ten-year time horizon. One-way and probabilistic sensitivity analyses (PSA) were performed. Costs are reported in 2020 USD ($). Findings: The economic cost per person was$0.27 for MDA and $0.43 for school-based targeted PC. MDA in Dak Lak will cost$472,000 per year, while school-based targeted PC will cost $117,000. Over 10 years, MDA is estimated to avert an additional 121,465 DALYs; 4,019,262 hookworm infection-years, and 765,844 moderate-to-heavy intensity hookworm infection-years compared to school-based targeted PC. The ICER was$28.55 per DALY averted; $0.87 per hookworm infection-years averted, and$4.54 per moderate-to-heavy intensity hookworm infection-years averted. MDA was cost-effective in all PSA iterations. Interpretation: In areas where hookworm predominates and adults suffer a significant burden of infection, MDA is cost effective compared to school based targeted PC and is the best strategy to achieve global targets. \</p

Ion Dynamics and CO2 Absorption Properties of Nb-, Ta-, and Y-Doped Li2ZrO3 Studied by Solid-State NMR, Thermogravimetry, and First-Principles Calculations

Among the many different processes proposed for large-scale carbon capture and storage (CCS), high temperature CO2 looping has emerged as a favorable candidate due to the low theoretical energy penalties that can be achieved. Many different materials have been proposed for use in such a process, the process requiring fast CO2 absorption reaction kinetics as well as being able to cycle the material for multiple cycles without loss of capacity. Lithium ternary oxide materials, and in particular Li2ZrO3, have displayed promising performance, but further modifications are needed to improve their rate of reaction with CO2. Previous studies have linked rates of lithium ionic conduction-with CO2 absorption in similar materials, and in this work we present work aimed at exploring the effect of aliovalent doping on the efficacy of Li2ZrO3 as a CO2 sorbent. Using a combination of X-ray powder diffraction, theoretical calculations, and solid-state nuclear magnetic resonance, we studied the impact of Nb, Ta, and Y doping on the structure, Li ionic motion, and CO2 absorption properties of Li2ZrO3. These methods allowed us to characterize the theoretical and experimental doping limit into the pure material, suggesting that vacancies formed upon doping are not fully disordered but instead are correlated to the dopant atom positions, limiting the solubility range. Characterization of the lithium motion using variable-temperature solid-state nuclear magnetic resonance confirms that interstitial doping with Y retards the movement of Li ions in the structure, whereas vacancy doping with Nb or Ta results in a similar activation energy as observed for nominally pure Li2ZrO3. However, a marked reduction in the CO2 absorption of the Nb- and Ta-doped samples suggests that doping also leads to a change in the carbonation equilibrium of Li2ZrO3, disfavoring the CO2 absorption at the reaction temperature. This study shows that a complex mixture of structural, kinetic, and dynamic factors can influence the performance of Li-based materials for CCS and underscores the importance of balancing these different factors in order to optimize the process

The value-add of tailored seasonal forecast information for industry decision-making

There is a growing need for more systematic, robust and comprehensive in-formation on the value-add of climate services from both the demand and supply sides. There is a shortage of published value-add assessments which focus on the decision-making context, involve participatory or co-evaluation approaches, avoid over-simplification and address both the quantitative (e.g. economic) and qualitative (e.g. social) value of climate services. The twelve case studies which formed the basis of the European Union-funded SECLI-FIRM project were co-designed by industrial and research partners in order to address these gaps, focusing on the use of tailored sub-seasonal and seasonal forecasts in the energy and water industries. For eight of these case studies it was pos-sible to apply quantitative economic valuation methods: econometric modelling was used for five case studies while three case studies used both cost-loss (relative economic value) analysis and avoided costs. The case studies illustrate the challenges in attempting to produce quantitative estimates of the economic value add of these forecasts. At the same time, many of them highlight how practical value for users – transcending the actual economic value – can be enhanced, for example, through the provision of climate services as an exten-sion to their current use of weather forecasts and with the visualisation tailored towards the user

Procalcitonin Is Not a Reliable Biomarker of Bacterial Coinfection in People With Coronavirus Disease 2019 Undergoing Microbiological Investigation at the Time of Hospital Admission

Abstract Admission procalcitonin measurements and microbiology results were available for 1040 hospitalized adults with coronavirus disease 2019 (from 48 902 included in the International Severe Acute Respiratory and Emerging Infections Consortium World Health Organization Clinical Characterisation Protocol UK study). Although procalcitonin was higher in bacterial coinfection, this was neither clinically significant (median [IQR], 0.33 [0.11–1.70] ng/mL vs 0.24 [0.10–0.90] ng/mL) nor diagnostically useful (area under the receiver operating characteristic curve, 0.56 [95% confidence interval, .51–.60]).</jats:p

Implementation of corticosteroids in treating COVID-19 in the ISARIC WHO Clinical Characterisation Protocol UK:prospective observational cohort study

BACKGROUND: Dexamethasone was the first intervention proven to reduce mortality in patients with COVID-19 being treated in hospital. We aimed to evaluate the adoption of corticosteroids in the treatment of COVID-19 in the UK after the RECOVERY trial publication on June 16, 2020, and to identify discrepancies in care. METHODS: We did an audit of clinical implementation of corticosteroids in a prospective, observational, cohort study in 237 UK acute care hospitals between March 16, 2020, and April 14, 2021, restricted to patients aged 18 years or older with proven or high likelihood of COVID-19, who received supplementary oxygen. The primary outcome was administration of dexamethasone, prednisolone, hydrocortisone, or methylprednisolone. This study is registered with ISRCTN, ISRCTN66726260. FINDINGS: Between June 17, 2020, and April 14, 2021, 47 795 (75·2%) of 63 525 of patients on supplementary oxygen received corticosteroids, higher among patients requiring critical care than in those who received ward care (11 185 [86·6%] of 12 909 vs 36 415 [72·4%] of 50 278). Patients 50 years or older were significantly less likely to receive corticosteroids than those younger than 50 years (adjusted odds ratio 0·79 [95% CI 0·70–0·89], p=0·0001, for 70–79 years; 0·52 [0·46–0·58], p80 years), independent of patient demographics and illness severity. 84 (54·2%) of 155 pregnant women received corticosteroids. Rates of corticosteroid administration increased from 27·5% in the week before June 16, 2020, to 75–80% in January, 2021. INTERPRETATION: Implementation of corticosteroids into clinical practice in the UK for patients with COVID-19 has been successful, but not universal. Patients older than 70 years, independent of illness severity, chronic neurological disease, and dementia, were less likely to receive corticosteroids than those who were younger, as were pregnant women. This could reflect appropriate clinical decision making, but the possibility of inequitable access to life-saving care should be considered. FUNDING: UK National Institute for Health Research and UK Medical Research Council

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead