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Modeling and Prediction of Conducted Electromagnetic Interference in Phase-Shifted Full-Bridge Converters
Get PDFThe 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
Get PDFThere 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
Evaluating the effect of probiotics on severe necrotising enterocolitis in preterm infants born before 32 weeks gestation in England and Wales: a propensity-matched population study
Get PDFBackground: Necrotising enterocolitis (NEC) remains an important cause of morbidity and mortality in preterm infants. This study aimed to examine whether probiotics reduce the risk of severe NEC and other key neonatal morbidities including late onset sepsis and mortality. Methods: Retrospective study using the United Kingdom National Neonatal Research Database. Infants <32 weeks gestation in England and Wales (01/01/2016–31/12/2022) were included if alive on day four, without major congenital anomaly. A propensity score matched approach was applied matching for gestational age cohorts, birth year epochs and 17 further items. Comparators were infants who were exposed or not to probiotics within 14 days. Primary outcome was severe NEC (confirmed at laparotomy or postmortem or listed primary cause of death). Parent focus groups and former NICU patients supported this study but did not contribute to design or writing. Findings: 48,048 infants (45.2% (21,695/48,048) female), median gestational age 29.4 weeks (IQR 27.4–30.9) were included; 25.3% (12,161/48,048) were exposed to at least one of five available probiotics. 3.6% (1728/48,048) had severe NEC. Of 16,586 infants (8293 exposed and 8293 unexposed) in the propensity-matched analysis, incidence and odds ratios (OR) (95% CI) for exposed versus unexposed for severe NEC was 3.3% versus 4.2%, OR 0.80 (0.72–0.89); other definitions of NEC yielded similar results. Incidence for late onset sepsis (10.8% versus 11.5%, OR 0.94 (0.90–0.97)) and survival to discharge (96.6% versus 94.2%, OR 1.76 (1.65–1.88)). In infants <28 weeks gestation, severe NEC (8.7% versus 9.8%, OR 0.88 (0.82–0.93) and for ≥28 weeks (1.0% versus 1.7%, OR 0.59 (0.47–0.73). Interpretation: Probiotics were associated with a reduction in severe NEC including in those <28 weeks gestation. We currently recommend neonatal units not already using probiotics, to consider the introduction of products meeting appropriate recommendations, in the context of their local morbidity rates
The development of the legend to the Provisional Soil Map of East Africa as a case study in colonial soil science
Get PDFThe Provisional Soil Map of East Africa (PSMEA), published in 1936, was produced by soil scientists in what were then British East African territories. It was an innovative contribution to soil mapping, summarising available information and communicating its incomplete and patchy distribution to the user. In this paper we examine the emergence of the map legend, using proceedings from two key meetings convened for East African soil chemists in 1932 and 1934, and associated correspondence, notes and publications. We consider the international context of the map's production, focusing on attempts to coordinate the efforts of colonial soil scientists in Britain's African territories, and the emergence of an international agenda to map soils at global scale in the aftermath of the formation of the International Soil Science Society (ISSS) (now International Union of Soil Sciences). We examine evidence for the attitudes to indigenous soil knowledge among colonial scientists at the time, showing how this perspective was marginalised, even though it underpinned research in Zambia. We show how, contrary to common assumptions about colonial science, the network behind the East African map was connected to international deliberations on soil survey and made innovative contributions while critiquing proposals from key international experts. We also show the importance of exchange of ideas between the East African team and Colin G. Trapnell, in Zambia. We then outline the later influence of the East African map, and its connections to D'Hoore's Soil Map of Africa
White matter resection and verbal memory deficits after temporal lobe epilepsy surgery
Get PDFTemporal lobe resection for focal, drug-resistant temporal lobe epilepsy (TLE) causes verbal memory deficits in 30% of left hemisphere-operated patients. Structural, functional and computational modelling have shown a widespread structural and functional memory network with hubs in critical brain regions including the hippocampus, subcortical and neocortical regions. We hypothesized that damage to white matter pathways forming a network involving cortical and subcortical regions may be responsible for postoperative memory problems. In this study, we measured verbal memory encoding (immediate recall) and retrieval (delayed recall) outcome at three timepoints (preoperative, 3- and 12-month postoperatively) in 146 left TLE patients who underwent temporal lobe surgery and evaluated the impact of white matter tract section on verbal memory. Outcome was measured by the change in scores from preoperative to 3- and 12-month postoperatively and via the reliable change index. Utilizing resection masks from pre- and postoperative T1 scans, an atlas-based analysis utilizing reconstructions of the ventral cingulum and fornix confirmed these tracts involvement in verbal encoding but not retrieval. Using preoperative diffusion MRI (dMRI) reconstructions with resection masks to estimate the percentage of fibre bundle transection, we found that the ventral cingulum was significantly related to verbal encoding change and the fornix was related to verbal retrieval across both 3- and 12-month timepoints. Investigating volumes of ventral cingulum and fornix from postoperative dMRI reconstruction revealed that greater volume remaining of the ventral cingulum and fornix was related to less decline in verbal encoding but not retrieval. Our results suggest that verbal encoding may be supported by direct and indirect connections between the medial temporal lobe and subcortical regions with memory deficits arising from their transection. Verbal retrieval may rely on a greater neocortical network. These findings may inform a revised surgical approach to minimize damage to the fornix and ventral cingulum to optimize memory outcome, but recognizing the potential for worse seizure outcome with less ventral cingulum resections
Sex associated biomarker differences in Chronic Kidney Disease progression and mortality
Get PDFBackground Males with chronic kidney disease (CKD) experience worse outcomes than females, a difference not fully explain ed by comorbidities or sociocultural factors. We explored whether sex-based differences in biomarkers could account for this difference in risk. Methods Our study included 1,680 male and 1,204 female participants with non-dialysis-dependent CKD and 84 controls from NURTuRE-CKD, a prospective multicentre cohort study. Twenty-one biomarkers relating to kidney injury and fibrosis, inflammation, and cardiovascular stress were measured. Outcomes were kidney failure (estimated glomerular filtration rate (eGFR) <15 ml/min/1.73 m² or kidney replacement therapy) and all-cause mortality. Multivariable Cox and Fine and Gray models assessed outcomes by sex. ANCOVA compared biomarker values between males and females adjusted for eGFR and urine albumin to creatinine ratio (UACR). Results Sex differences in biomarker concentrations were observed in both controls and CKD participants. In male controls, higher levels of urinary Vascular Endothelial Growth Factor, Tissue Inhibitor of Metalloproteinases-1 and blood Neutrophil Gelatinase-Associated Lipocalin, soluble Cluster of Differentiation 40, soluble Cluster of Differentiation 40 Ligand, soluble Tumour Necrosis Factor Receptor 1, Monocyte Chemoattractant Protein-1, and High-Sensitivity Cardiac Troponin T were observed. In males with CKD, additionally higher levels of urine Collagen Type I Alpha 1, blood Kidney Injury Molecule-1, Growth Differentiation Factor-15, and N-terminal pro-B-type Natriuretic Peptide. were noted, while females with CKD showed higher urinary Osteoactivin, KIM-1, Matrix Metalloproteinase-9 and blood Fibroblast Growth Factor-23, concentrations. In Cox proportional hazards models adjusted for demographics, kidney function, comorbidities, social factors, and medications, male sex was associated with a higher risk of kidney failure (hazard ratio (HR) 1.28, 95% confidence interval (CI): 1.09–1.50) and mortality (HR 1.29, 95% CI: 1.05–1.60). Male sex was no longer associated with higher risk after adjustment for biomarker differences, kidney failure (HR 1.18, 95% CI: 0.97, 1.43) and mortality (HR 1.17, 95% CI: 0.98, 1.58). Conclusions Male sex was associated with a higher risk of kidney failure and mortality, despite adjustment for demographic, clinical, and treatment factors. Males had higher levels of inflammatory and extracellular matrix deposition biomarkers. In contrast, females showed higher levels of matrix turnover and degradation markers. After adjustment for these biomarker differences, the elevated risk associated with male sex was eliminated, suggesting a biological basis for the observed sex difference in outcomes
IHPE Position Statement: Mental Health at Work
Get PDFMental health at work is a major public health challenge with significant social, economic and equity implications. Globally, depression and anxiety are among the leading causes of disability, accounting for an estimated 12 billion working days lost each year and costing the global economy approximately US$1 trillion annually in lost productivity (WHO, 2022; WHO, 2024). Prior to the COVID- 19 pandemic, around 15% of working-age adults were estimated to be living with mental ill-health, with many attributing poor mental health to past or present working conditions (WHO, 2022). In the UK, mental ill-health is now one of the leading causes of sickness absence, presenteeism and labour market inactivity (ONS, 2023; Hassard et al., 2023). This is part of a broader global trend, with international policy bodies and research evidence highlighting rising rates of mental ill-health worldwide. The pandemic and subsequent changes in working patterns have further intensified psychosocial risks, including work intensification, job insecurity, isolation and poor work-life boundaries. These risks are unevenly distributed, disproportionately affecting people in deprived communities, those in insecure or low-paid work, disabled people, and workers facing discrimination related to ethnicity, gender or other protected characteristics. Work is a key social determinant of health. As such, promoting mental health at work aligns directly with IHPE’s commitment to reducing health inequalities, advancing social justice, and supporting health across the life course (Watson et al., 2021). Mental health at work must therefore be understood not solely as an individual issue, but as a collective responsibility shaped by organisational practices, leadership, job design, and wider policy contexts
Enhanced Molecular Stacking Enabled by Photo‐Induced Cosslinking of Hole Transport Materials for High‐Performance QLED
Get PDFSolution-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
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