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Modeling and Prediction of Conducted Electromagnetic Interference in Phase-Shifted Full-Bridge Converters
Full text linkThe phase-shifted full-bridge (PSFB) converter, featuring simple topology and soft-switching, has been extensively employed in medium-to-high power conversions. As an isolated topology with multiple power switches, the PSFB converter is characterized by multiple noise sources and multiple noise propagation routes, leading to complex and harsh electromagnetic interference (EMI) challenges. In this article, the equivalent common-mode (CM) and differential-mode (DM) noise models for the PSFB converter are built. Then, the CM and DM spectral properties are presented, and the worst cases of the CM and DM noises over various input voltage and load situations are obtained. The analysis indicates that the CM noise is concentrated at odd harmonics of the switching frequency, and its worst spectrum occurs at the fundamental frequency with high input voltage and light load conditions; while the DM noise is concentrated at even harmonics of the switching frequency, and its worst spectrum occurs at the second harmonic frequency with high input voltage and full load conditions. A prototype is fabricated in the laboratory, and tested data are provided to confirm the effectiveness of theoretical analysis
Investigation of varenicline and tropisetron in latent inhibition and novel object recognition in mice
Full text linkThere is currently no treatment for cognitive-impairment associated with schizophrenia (CIAS). Animal and human studies suggest that nicotinic cholinergic agonists and 5-HT3 antagonists have potential therapeutic benefits. We investigated whether co-administration of varenicline, an alpha4beta2 nAChR partial agonist and alpha7 nicotinic receptor agonist, and tropisetron, a 5-HT3 antagonist and alpha7 nicotinic receptor agonist is pro-cognitive in male c57/Bl6 mice. We first assessed Latent inhibition (LI) an associative learning process of learning to ignore irrelevant stimuli. We report no effect of tropisetron on LI (0.01, 0.04, 0.4 mg/kg s.c.). Varenicline at 0.5 mg/kg s.c. potentiated LI. Co-administration of tropisetron 0.4 mg/kg s.c. and 0.5 mg/kg s.c. varenicline abolished varenicline’s potentiation of LI. In 24 h retention of novel object recognition (NOR) where memory performance (discrimination-index) is poor in controls there was no effect of varenicline or tropisetron. When varenicline (0.5 mg/kg) and tropisetron (0.01, 0.1, 1.0 mg/kg) were co-administered NOR discrimination-index was higher compared to controls. These data indicate that varenicline enhances LI when low in controls, demonstrate an interaction between varenicline and tropisetron in LI and suggest synergistic interaction between tropisetron and varenicline to potentiate NOR memory merits further investigation. These findings have implications for treatment of CIAS and disorders with cognitive impairment
A Wireless Power Transfer System Based on Hybrid Self-switching of Coupled Inductors
Full text linkThis paper proposes a wireless power transfer system based on hybrid self-switching of coupled inductor that not only realizes constant current (CC)/constant voltage (CV) output but also effectively copes with a variety of abnormal working conditions in the charging process by switching on the secondary side. First, the LCC-LCC/S self-switching composite topology is presented, and the CC/CV switching is achieved by utilizing a coupled inductor with a center tap based on the LCC compensation topology. The working principle of the CC/CV topology and the parameter calculation flow are analyzed in detail. Subsequently, the impedance, output characteristics, and switching characteristics of the constant current/constant voltage topology are simulated and analyzed. Additionally, the topology's stability under abnormal working conditions, such as the missing adjacency, load short-circuit, and load open-circuit, is analyzed. Finally, an experimental platform is constructed with the objective of verifying the feasibility and effectiveness of the proposed scheme. The experimental results demonstrate that the proposed charging system exhibits excellent constant current and constant voltage output characteristics without the need for additional inductor capacitance. The proposed system has a maximum output efficiency of 89.6%, a maximum current of 5.3A, and a maximum voltage of 23V, which fully meets the requirements of constant current and constant voltage wireless charging
Enhanced Molecular Stacking Enabled by Photo‐Induced Cosslinking of Hole Transport Materials for High‐Performance QLED
Full text linkSolution-processed quantum dot light-emitting diodes (QLEDs) are attractive candidates for next-generation displays. A critical component of high-performance QLEDs is a robust hole-transporting layer (HTL) with well-aligned energy levels. However, conventional polymer HTLs often suffer from disordered molecular stacking and severe tail states, leading to insufficient hole transport mobility, imbalanced carrier transport efficiency, and consequently, degraded device performance. To address these challenges, this study proposes a crosslinking-induced structural reforming strategy to optimize the polymer HTLs. As proof of this concept, poly(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-sec- butylphenyl)) diphenylamine) (TFB), the commonly used HTL material, is modified by adding a photo-crosslinking agent. The crosslinked TFB layers exhibit enhanced molecular ordering and narrowed tail states, suggesting reduced energetic disorder. The red QLED devices using crosslinked TFB as the HTL have shown significant improvement in performance, achieving peak external quantum efficiency (EQE) of 24.62% and current efficiency (CE) of 24.3 cd A−1. Furthermore, the operational stability is also improved, with a nearly three-fold enhancement compared to the control sample. Additionally, the photo-crosslinking process enables the precise patterning of TFB films, supporting the fabrication of pixelated HTLs. These results highlight the potential of crosslinked HTLs for enhancing performance and promoting commercialization in next-generation QLED displays
Tree diversity is changing across tropical Andean and Amazonian forests in response to global change
No full textClimate and atmospheric changes are impacting forest function and structure worldwide, but their effects on tropical forest diversity are unclear. Nowhere is the scientific challenge greater than in the Andes and the Amazon, which together include the world’s most diverse forests. Here, using 406 permanent plots spanning four decades of intact lowland and montane forest dynamics, we test for long-term change in species richness and assess the influence of climate and other variables. We show that, at a continental scale, species richness appears stable, but this masks substantial regional variation. Species richness increased in Northern Andean and Western Amazon plots, yet declined in the Central Andes, Guyana Shield and Central-Eastern Amazon. Overall, warmer, drier and more seasonal forests lost species, while those at higher elevations, in less fragmented areas and with faster rates of tree turnover experienced increases. Region-specific drivers, particularly precipitation seasonality and demographic factors, modulated these trends. The results highlight the diverse ways in which Amazon–Andes forests are changing and underscore the critical need to preserve large-scale ecosystem integrity to maintain local tree diversity. By doing so, Northern Andean forests in particular could serve as an important refuge for species increasingly displaced by climate change
Effect of prior antiplatelet therapy on recurrence in patients with acute cerebral ischaemia: data from the triple antiplatelets for reducing dependency after ischaemic stroke (TARDIS) randomised trial
No full textBackground: Data regarding management of patients already on an antiplatelet when presenting with an ischaemic stroke or transient ischaemic attack (TIA) are limited. This secondary analysis of the triple antiplatelets for reducing dependency in ischaemic stroke (TARDIS) trial explored clinical outcomes across prior antiplatelet groups. Methods: TARDIS was an international prospective-randomised open-label blinded-endpoint trial assessing 30days of triple vs. guideline antiplatelet therapy in patients with acute ischaemic stroke or TIA. The number of pre-stroke/TIA antiplatelet agents was collected pre-randomisation. The primary outcome was the combined incidence of, and dependency from, any recurrent stroke (using the modified Rankin Scale) or TIA within 90days analysed using ordinal logistic regression with adjustment for prognostic factors. Baseline imaging features of brain frailty were adjudicated centrally by neuroimaging experts. Results: 1080/3096 (34.9%) participants were on an antiplatelet agent prior to their stroke/TIA and were older, more likely to be male, had more co-morbidities and dependency, and more baseline imaging features of brain frailty than those not on prior antiplatelets. They had a higher incidence of, and dependency from, recurrent stroke or TIA at day 90: 86 (8%) vs. 112 (5.6%), adjusted common OR 1.40, 95%CI 1.02–1.92, p = 0.036; the result was neutralised when adjusted for brain frailty. Randomisation to triple vs. guideline therapy did not influence this effect. Conclusions: Participants taking prior antiplatelets were frailer and had a higher incidence and severity of recurrent stroke or TIA at 90days compared with those not on prior antiplatelets prior to adjustment for brain frailty. Trial registration: ISRCTN47823388
‘clogged by masses of paperwork’: Britain’s Secret Intelligence Service (SIS/MI6), Whitehall and the early Cold War, 1949–1956
No full textThis article examines the work and organisation of Britain’s Secret Intelligence Service (SIS or MI6) in the early Cold War, broadening the study of the service beyond the 1949 cut-off date of the service’s authorised history. It shows that whilst efforts to reform the service for peacetime had started before the end of the Second World War, this process remained incomplete over a decade later. It also explores SIS’s relations with the rest of Whitehall, especially liaison with customers on the main Soviet target, and the financial aspects of the service’s work and the oversight of HM Treasury
Remittances as translocal collateral: How microfinance profitably sustains precarity in Cambodia
No full textIn this paper, we explore how commercialised microfinance institutions and banks leverage remittance-related information to assess and provide microfinance loans to households in Cambodia. We argue that (microfinance) debt regimes profitably sustain precarity in the Cambodian translocal context. Building from five studies undertaken between 2014 and 2022, we illustrate our argument through a two-pronged approach. First, we critically unpack the empirical realities of the relationship between migration, remittances, and debt repayment. We show that the lending strategies of microfinance institutions and banks take into account the remittances received by rural households from adult children who have moved to cities or overseas. It is the social obligations within the family to remit money home – or ‘filial debts’ – that are being collateralised. As the monetary expression of these social obligations, remittances serve as a form of what we call ‘translocal collateral’ which (re)constitutes connections among family members across space to mitigate repayment risks for the microfinance industry, often at the expense of the well-being of its borrowers. Second, we contend that these financial institutions’ lending practices – and the development programmes and policies that promote them – rely on translocal strategies of social reproduction that are unstable and fragile. Sudden interruptions in remittance flows can have significant ramifications for rural households, forcing them to deal not only with decreases in income but also looming debts to repay. This should serve as a call for caution among development practitioners and policymakers promoting the leveraging of remittances for financial inclusion
Machine learning prediction of moderate‐to‐severe acute kidney injury after ICU admission and cardiac surgery with urine trace elements
Full text linkBackground: Acute kidney injury (AKI) is common and linked to poor outcomes, but early detection remains challenging. Previous research identified urinary trace elements (TE) as early AKI biomarkers in intensive care unit (ICU) or cardiac surgery patients. We aimed to explore whether urinary TE enhance machine learning (ML) models for AKI prediction. Methods: We constructed ML models using the ICU cohort. We filtered the variables and optimized hyperparameters before predicting Kidney Disease: Improving Global Outcomes stage 2–3 AKI using eight ML classifiers: light gradient boosting machine (LightGBM), random forest (RF), ML logistic regression, support vector machine, multilayer perceptron, eXtreme gradient boosting (XGBoost), Gaussian Naive Bayes and k-nearest neighbors. External validation was performed in the cardiac surgery cohort. Results: Among 149 ICU patients (median age 56.0 [interquartile range (IQR): 43.5–67.0], 63.1% male), 25 developed stage 2–3 AKI; among 144 cardiac surgery patients (median age 70.0 [IQR: 62.0–76.0], 72.9% male), 12 developed stage 2–3 AKI. Each ML in the internal validation had area under the curve (AUC) above.7, with XGBoost having the highest (.813); LightGBM had the second highest AUC (.799), highest G-mean (.567) and F1-score (.545). In external validation, RF had the highest AUC (.740), XGBoost had the highest G-mean (.289) and F1-score (.286). Age, strontium and boron were consistently ranked among the top five most important features in LightGBM, RF and XGBoost. Conclusion: ML models primarily based on urinary TE can identify AKI risk in both clinical groups (ICU and cardiac surgery), with LightGBM, RF and XGBoost serving as high-performance models for early prediction of stage 2–3 AKI
The incidence of aneuploidy and mosaicism in 2,045 genotyped cattle blastocysts
No full textChromosomal abnormalities are the most common cause of developmental arrest in mammalian embryos. They can be present consistently in all cells of the embryo or occur as admixtures of karyotypically distinct lineages (mosaics). The estimated incidence of mosaicism ranges from 14% to 82% in human embryo biopsies at the blastocyst stage. In cattle, mosaicism is not well described at a whole-genome level, with findings limited to sex chromosomes. Here, we conducted a retrospective analysis of published data spanning three studies from our laboratory to establish the incidence and nature of mosaicism in 2,045 bovine blastocysts genotyped using single nucleotide polymorphism-based approaches. We classified mosaic embryos as those where the inner cell mass and trophectoderm differed in ploidy and/or where embryos had a percentage of cells with aneuploidy ranging from 20% to 80%. We report an aneuploidy incidence of 15.2% (n = 311/2,045), with 25.6% of the aneuploid embryos (80/311) being mosaic. Mosaicism was particularly common (87.5%, n = 7/8) in embryos affected by multiple types of chromosomal errors and in embryos affected only by segmental aneuploidies (50.0%, n = 9/18). The chromosomal abnormalities with the highest incidence of mosaicism were segmental aneuploidies (48.1%, n = 13/27). Most errors leading to mosaicism had a paternal origin (44.9%, n = 22/49), followed by post-zygotic errors (37.3%, n = 19/51). Our results reveal an incidence of mosaicism in bovine embryos similar to that of human embryos. Additionally, we demonstrate that ploidy and mosaicism screening can be performed in embryos using the same single nucleotide polymorphism genotyping data obtained to calculate genomic estimated breeding values
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