Search results

(121 - 140 of 111,757)

Pages

Akkerman, N.N.W.; Langman, P.F.; Lipscomb, S. 2024

Spycraft: from the Elizabethans to the Restoration

Sound

metadata only

The 16th and 17th centuries were a crucial time for spycraft, full of political intrigue and diplomatic subterfuge. Walsingham was known as a 'Spy Master', but there were many, all vying for... Show moreThe 16th and 17th centuries were a crucial time for spycraft, full of political intrigue and diplomatic subterfuge. Walsingham was known as a 'Spy Master', but there were many, all vying for attention from the Crown.But how did they and their spies operate? Professor Suzannah Lipscomb welcomes Pete Langman and Professor Nadine Akkerman to delve into the practices of espionage and reveal how the line between spy and criminal was easily blurred depending on who was in favour, and who was betrayed.Presented by Professor Suzannah Lipscomb. Show less

Shamaprasad, P.; Nadaban, A.; Iacovella, C.R.; Gooris, G.S.; Bunge, A.L.; Bouwstra, J.A.; McCabe, C. 2024

The phase behavior of skin-barrier lipids: a combined approach of experiments and simulations

Article / Letter to editor

open access

Skin barrier function is localized in its outermost layer, the stratum corneum (SC), which is comprised of corneocyte cells embedded in an extracellular lipid matrix containing ceramides (CERs),... Show moreSkin barrier function is localized in its outermost layer, the stratum corneum (SC), which is comprised of corneocyte cells embedded in an extracellular lipid matrix containing ceramides (CERs), cholesterol (CHOL), and free fatty acids (FFAs). The unique structure and composition of this lipid matrix are important for skin barrier function. In this study, experiments and molecular dynamics simulation were combined to investigate the structural properties and phase behavior of mixtures containing nonhydroxy sphingosine CER (CER NS), CHOL, and FFA. X-ray scattering for mixtures with varying CHOL levels revealed the presence of the 5.4 nm short periodicity phase in the presence of CHOL. Bilayers in coarse-grained multilayer simulations of the same compositions contained domains with thicknesses of approximately 5.3 and 5.8 nm that are associated with elevated levels, respectively, of CER sphingosine chains with CHOL, and CER acyl chains with FFA chains. The prevalence of the thicker domain increased with decreasing CHOL content. This might correspond to a phase with ∼5.8 nm spacing observed by x-rays (other details unknown) in mixtures with lower CHOL content. Scissoring and stretching frequencies from Fourier transform infrared spectroscopy (FTIR) also indicate interaction between FFA and CER acyl chains and little interaction between CER acyl and CER sphingosine chains, which requires CER molecules to adopt a predominantly extended conformation. In the simulated systems, neighbor preferences of extended CER chains align more closely with the FTIR observations than those of CERs with hairpin ceramide chains. Both FTIR and atomistic simulations of reverse mapped multilayer membranes detect a hexagonal to fluid phase transition between 65 and 80°C. These results demonstrate the utility of a collaborative experimental and simulation effort in gaining a more comprehensive understanding of SC lipid membranes. Show less

Munar-Palmer M.; Santamaría-Hernando S.; Liedtke J.; Ortega D.R.; López-Torrejón G.; Rodríguez-Herva J.J.; ... ; López-Solanilla E. 2024

Chemosensory systems interact to shape relevant traits for bacterial plant pathogenesis

Article / Letter to editor

open access

Kamdem, S.; Ojongnkpot, C.; Pinxteren, L.M.C. van 2024

Decolonizing Cameroon’s language policies: a critical assessment

Article / Letter to editor

open access

Due to its colonial history and prevalent multilingualism, Cameroon is a country where language policies have profoundly impacted socioeconomic and political life. Cameroon has 273 local languages... Show moreDue to its colonial history and prevalent multilingualism, Cameroon is a country where language policies have profoundly impacted socioeconomic and political life. Cameroon has 273 local languages and two official languages, English and French. The two official languages have been a crystallization point for discontent and civil unrest, leading to secessionist sentiments and violence. In this paper, we assess Cameroon’s language policies, firstly by providing a brief historical and legal overview based in the literature. We then present a new decolonial analytical framework, building on but extending existing theoretical frameworks. Our new analysis shows that a transition to using indigenous languages in formal education and other domains is not necessary at present. However, we argue that such a transition will become unavoidable in future. We show that it will be practically possible to use a limited number of indigenous languages as mediums of instruction, building on existing bilingualisms in the country. We believe these languages should be chosen using rational criteria and we introduce an approximate assessment of which languages are easy to learn and teach, and for speakers of which other languages. The transition we foresee requires planning and preparation. A different approach to Cameroon’s languages may help in building national unity and healing national wounds in the areas of sociolinguistic power-sharing and interregional cohabitation. We expect that our approach also holds benefits for other African countries. Show less

Wolff, S.C.A.; Zardo, F. 2024

The role of sub-national actors in coordinative Europeanisation: insights from the digitalisation of asylum services

Article / Letter to editor

open access

Coordinative Europeanisation is a powerful frame to explain the rapid response of EU institutions in times of permanent emergency. So far, though, little is known about sub-national actors’ role in... Show moreCoordinative Europeanisation is a powerful frame to explain the rapid response of EU institutions in times of permanent emergency. So far, though, little is known about sub-national actors’ role in this process. Moving away from a state-centric approach, this article investigates the role of sub-national actors through the case study of the digital provision of services to asylum seekers. Given the field’s high salience and state-centric nature, this article elucidates the critical role of European sub-national actors, particularly at the municipality level, to accelerate the digital provision of services to refugees. Comparing 3 European cities (Paris, Palermo and Malaga), we argue that sub-national actors can play a role in coordinative Europeanisation and that 2 main mechanisms may enable it. In the cases observed, discursive coordination around humanitarian duty facilitated the emergence of similar digital solutions across countries. Subsequently, horizontal and vertical networking was used by sub-national actors to legitimise their actions and enhance their anchoring in processes of coordinative Europeanisation Show less

Alcantara-Rodriguez, M.; Andel, T.R. van; Françozo, M. 2024

Nature portrayed in images in Dutch Brazil: tracing the sources of the plant woodcuts in the Historia Naturalis Brasiliae (1648)

Article / Letter to editor

open access

Andreeva, V.D.; Regeni, I.; Yang, T.; Elmanova, A.; Presselt, M.; Dietzek-Ivansic, B.; Bonnet, S.A. 2024

Red-to-blue triplet: triplet annihilation upconversion for calcium sensing

Article / Letter to editor

open access

Triplet-triplet annihilation upconversion is a bimolecular process converting low-energy photons into high-energy photons. Here, we report a calcium-sensing system working via triplet-triplet... Show moreTriplet-triplet annihilation upconversion is a bimolecular process converting low-energy photons into high-energy photons. Here, we report a calcium-sensing system working via triplet-triplet annihilation (TTA) upconverted emission. The probe itself was obtained by covalent conjugation of a blue emitter, perylene, with a calcium-chelating moiety, and it was sensitized by the red-light-absorbing photosensitizer palladium(II) tetraphenyltetrabenzoporphyrin (PdTPTBP). Sensing was selective for Ca2+ and occurred in the micromolar domain. In deoxygenated conditions, the TTA upconverted luminescence gradually appeared upon adding an increasing concentration of calcium ions, to reach a maximum upconversion quantum yield of 0.0020. Show less

Marciello, M.; Cusati, V.; Nicolosi, F.; Saavedra-Rubio, K.; Pierrat, E.; Thonemann, N.; Laurent, A. 2024

Evaluating the economic landscape of hybrid-electric regional aircraft: a cost analysis across three time horizons

Article / Letter to editor

under embargo until 2025-01-16

This article presents the results of a prospective cost analysis of future regional aviation solutions, specifically focusing on hybrid-electric regional aircraft for 50 passengers. The study spans three time horizons (short term, medium term, long term) and employs a validated workflow to estimate costs for various solutions, including conventional, hybrid-electric, and hydrogen-based architectures. A specialized cost model is introduced to assess the electric components of the powertrain, emphasizing maintenance expenses and energy costs. Despite the environmental promise of hybrid and electric solutions, the results reveal significantly higher direct operating costs (up to 69.8%) compared to conventional options. The study highlights the importance of targeted policies to incentivize sustainable alternatives, suggesting potential solutions such as discouraging kerosene-based aircraft and promoting sustainable aviation fuel. These insights provide valuable guidance for industry stakeholders navigating the path toward a more sustainable and economically viable aviation future.

Show less

Groen, R.A.; Barbero, F.L.; Fischer, S.E.; Dijkman, P.R.M. van; Bax, J.J.; Tushuizen, M.E.; ... ; Graaf, M.A. de 2024

Coronary artery calcium assessment on non-gated chest CT to optimize pre-operative cardiac screening in liver transplantation

Article / Letter to editor

open access

BackgroundGuidelines recommend standard pre-operative cardiac screening in all liver transplantation (LT) recipients, despite the relatively low prevalence of obstructive coronary artery disease.... Show moreBackgroundGuidelines recommend standard pre-operative cardiac screening in all liver transplantation (LT) recipients, despite the relatively low prevalence of obstructive coronary artery disease. Most LT recipients often have non-gated computed tomography (CT) performed of the chest and abdomen. This study evaluated the ability of coronary artery calcification (CAC) assessment on consecutively available scans, to identify a selection of low-risk patients, in whom further cardiac imaging can be safely withheld.MethodsLT recipients with prior non-gated CT chest-abdomen were included. CAC was visually scored on a semi-quantitative ordinal scale. Stress myocardial perfusion, coronary CT angiography (CCTA) and invasive coronary angiography (ICA) were used as golden standard. The sensitivity and specificity of CAC to exclude and predict obstructive CAD were assessed. In addition, peri- and postoperative mortality and cardiac events were analyzed.Results149 LT recipients (ranged 31–71 years) were included. In 75% of patients, no CAC and mild CAC could rule out obstructive CAD on CCTA and ICA with 100% certainty. The threshold of mild CAC had a sensitivity of 100% for both CCTA and ICA and a specificity of 91% and 68%, respectively. None of the patients with no or mild calcifications experienced peri- and post-operative cardiac events or died of cardiac causes.ConclusionVisual evaluation of CAC on prior non-gated CT can accurately and safely exclude obstructive CAD in LT recipients. Incorporation of these already available data can optimize cardiac screening, by safely withholding or correctly allocating dedicated cardiac imaging in LT recipients. Thereby, reducing patients' test burden and save health care expenses. Show less

Hendriks, A.C. 2024

EHRM 9 juli 2024, Savinovskikh e.a. t. Rusland, nr. 16206/19, ECLI:CE:ECHR:2024:0709JUD001620619, EHRC 2024/188, m.nt. A.C. Hendriks: ontzeggen van pleegzorg aan transgender man ongerechtvaardigd en niet in belang kinderen

Annotation

open access

Khalil, S.S.; Tawfik, N.S.; Spruit M. 2024

Federated learning for privacy-preserving depression detection with multilingual language models in social media posts

Article / Letter to editor

open access

Grasseni, C. 2024

Re-territorialising skills? Insights from ethnography on solidarity-economy food activism

Article / Letter to editor

open access

Assadi, H.; Alabed, S.; Li, R.; Matthews, G.; Karunasaagarar, K.; Kasmai, B.; ... ; Garg, P. 2024

Development and validation of AI-derived segmentation of four-chamber cine cardiac magnetic resonance

Article / Letter to editor

open access

Background Cardiac magnetic resonance (CMR) in the four-chamber plane ofers comprehensive insight into the volumetrics of the heart. We aimed to develop an artifcial intelligence (AI) model of time... Show moreBackground Cardiac magnetic resonance (CMR) in the four-chamber plane ofers comprehensive insight into the volumetrics of the heart. We aimed to develop an artifcial intelligence (AI) model of time-resolved segmenta‑ tion using the four-chamber cine. Methods A fully automated deep learning algorithm was trained using retrospective multicentre and multivendor data of 814 subjects. Validation, reproducibility, and mortality prediction were evaluated on an independent cohort of 101 subjects. Results The mean age of the validation cohort was 54 years, and 66 (65%) were males. Left and right heart parame‑ ters demonstrated strong correlations between automated and manual analysis, with a ρ of 0.91−0.98 and 0.89−0.98, respectively, with minimal bias. All AI four-chamber volumetrics in repeatability analysis demonstrated high correla‑ tion (ρ=0.99−1.00) and no bias. Automated four-chamber analysis underestimated both left ventricular (LV) and right ventricular (RV) volumes compared to ground-truth short-axis cine analysis. Two correction factors for LV and RV four-chamber analysis were proposed based on systematic bias. After applying the correction factors, a strong correlation and minimal bias for LV volumetrics were observed. During a mean follow-up period of 6.75 years, 16 patients died. On stepwise multivariable analysis, left atrial ejection fraction demonstrated an independent association with death in both manual (hazard ratio (HR)=0.96, p=0.003) and AI analyses (HR=0.96, p<0.001). Conclusion Fully automated four-chamber CMR is feasible, reproducible, and has the same real-world prognostic value as manual analysis. LV volumes by four-chamber segmentation were comparable to short-axis volumetric assessment. Show less

Jara, H.X.; Mideros Mora, A.; Palacio Ludeña, M.G. 2024

Política social, pobreza y desigualdad en el Ecuador: 1980-2021

Book editorial

metadata only

El libro analiza la política social en el Ecuador y sus transformaciones a lo largo de las últimas cuatro décadas, explorando cómo las relaciones sociales y los sistemas institucionales han...

El libro analiza la política social en el Ecuador y sus transformaciones a lo largo de las últimas cuatro décadas, explorando cómo las relaciones sociales y los sistemas institucionales han impulsado o limitado las nociones de bienestar, las políticas implementadas y los resultados obtenidos. Se toma como área de estudio una perspectiva amplia de la política social, desde los procesos que afectan las condiciones de la vida humana, los sistemas de políticas sociales desde lo público (el Estado) y sus instituciones, pero también las acciones de otros actores. El libro aborda el sistema tributario ecuatoriano, los programas de asistencia social, la seguridad social, los sistemas de salud y educación, la protección de niños, niñas y adolescentes, la incidencia de las reformas de impuestos directos y transferencias monetarias, y la evolución del bienestar desde una perspectiva multidimensional. De esta manera se logra un análisis amplio del proceso de construcción de un sistema de protección social o régimen de bienestar aún en desarrollo y disputa.

Show less

Izurieta, G.; Palacio Ludeña, M.G. 2024

Transformaciones y desafíos de la asistencia social en Ecuador: 1980-2021

Part of book or chapter of book

metadata only

Butcher, S.C.; Hirasawa, K.; Meucci, M.C.; Stassen, J.; Kuneman, J.H.; Pereira, A.R.; ... ; Bax, J.J. 2024

Prognostic implications and alterations in left atrial deformation following transcatheter aortic valve implantation

Article / Letter to editor

open access

Aims: To evaluate the prognostic implications of the left atrial reservoir strain–defined diastolic dysfunction (LARS-DD) grade in patients undergoing transcatheter aortic valve implantation (TAVI)... Show moreAims: To evaluate the prognostic implications of the left atrial reservoir strain–defined diastolic dysfunction (LARS-DD) grade in patients undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) and to determine whether post-TAVI LARS was more closely associated with new-onset atrial fibrillation than pre-TAVI LARS. Methods and results: Pre-TAVI LARS-DD was evaluated by speckle-tracking echocardiography and was assigned as Grade 0 to 1 (LARS ≥24%), Grade 2 (LARS 19–24%), and Grade 3 (LARS <19%). Patients were followed up for the primary endpoint of all-cause mortality from the date of TAVI. For the secondary endpoint, patients with pre- and post-TAVI LARS measurements and no history of atrial fibrillation were evaluated for the occurrence of new-onset atrial fibrillation. A total of 601 patients [median age 81 (76–85) years, 53% males] were included. Overall, 169 patients (28%) were LARS-DD Grade 0/1, 96 patients (16%) were LARS-DD Grade 2, and 336 (56%) were LARS-DD Grade 3. Over a median follow-up of 40 (interquartile range 26–58) months, a total of 258 (43%) patients died. In a comprehensive multivariable Cox regression model, the LARS-DD grade was independently associated with all-cause mortality [adjusted hazard ratio (HR) 1.28 per one-grade increase, 95% confidence interval (CI) 1.07–1.53, P = 0.007]. For the secondary endpoint of new-onset atrial fibrillation, a total of 285 patients were evaluated. Post-TAVI LARS (subdistributional HR 1.14 per 1% <20%, 95% CI 1.05–1.23, P = 0.0009), but not pre-TAVI LARS (P = 0.93), was independently associated with new-onset atrial fibrillation. Conclusion: An increased LARS-DD grade was independently associated with long-term post-TAVI survival in patients with severe AS. Post-TAVI LARS was closely related to the occurrence of new-onset atrial fibrillation. Show less

Pirie, M.D.; Bellstedt, D.U.; Bouman, R.W.; Fagúndez, J.; Gehrke, B.; Kandziora, M.; ... ; Forest, F. 2024

Spatial decoupling of taxon richness, phylogenetic diversity and threat status in the megagenus Erica (Ericaceae)

Article / Letter to editor

open access

Estimates of the number of vascular plant species currently under threat of extinction are shockingly high, with the highest extinction rates reported for narrow-range, woody plants, especially in... Show moreEstimates of the number of vascular plant species currently under threat of extinction are shockingly high, with the highest extinction rates reported for narrow-range, woody plants, especially in biodiversity hotspots with Mediterranean and tropical climates. The large genus Erica is a prime example, as a large proportion of its 851 species, all shrubs or small trees, are endemic to the Cape Floristic Region (CFR) of South Africa. Almost two hundred are known to be threatened and a further hundred are ‘Data Deficient’. We need to target conservation efforts and research to fill the most problematic knowledge gaps. This can be especially challenging in large genera, such as Erica, with numerous threatened species that are closely related. One approach involves combining knowledge of phylogenetic diversity with that of IUCN threat status to identify the most Evolutionarily Distinct and Globally Endangered (EDGE) species. We present an expanded and improved phylogenetic hypothesis for Erica (representing 65% of described species diversity) and combine this with available threat and distribution data to identify species and geographic areas that could be targeted for conservation effort to maximise preservation of phylogenetic diversity (PD). The resulting 39 EDGE taxa include 35 from the CFR. A further 32 high PD, data deficient taxa are mostly from outside the CFR, reflecting the low proportion of assessed taxa outside South Africa. The most taxon-rich areas are found in the south-western CFR. They are not the most phylogenetically diverse, but do include the most threatened PD. These results can be cross-referenced to existing living and seed-banked ex situ collections and used to target new and updated threat assessments and conservation action. Show less

Mylona, E. 2024

In-between categories: documenting Greek children’s legal belonging in the Suez Canal region

Article / Letter to editor

open access

This paper looks at the complex manner in which children were documented in Ottoman Egypt and their access to citizenship later in postcolonial Egypt. It discusses the making of social and... Show moreThis paper looks at the complex manner in which children were documented in Ottoman Egypt and their access to citizenship later in postcolonial Egypt. It discusses the making of social and political categories, like citizenship and statelessness, and how Greeks moved through those categories. This paper also analyzes how these categories were imposed, first by the Ottoman Empire and then by the Egyptian nation-state. The end of the Ottoman Empire in 1922, and the declaration of the Egyptian Republic in 1953, the Suez Crisis in 1956, the Arab-Israeli Wars in 1967 and 1973, and the new labor laws of the 1950s and 1960s, among other events, impacted Greeks and others who lived in Egypt at that time. The impact among Greeks in Suez Canal cities was particularly evident in the community’s cohesion, as most evacuated the cities in 1967 with almost everyone else following in 1973. These economic and political factors, and the social processes the community underwent, defined Greek children’s relation with the Egyptian postcolonial state. Show less

Rousel, J.; Mergen, C.; Bergmans, M.E.; Bruijnincx, L.J.; Kam, M.L. de; Klarenbeek, N.B.; ... ; Rissmann, R. 2024

Guselkumab treatment normalizes the stratum corneum ceramide profile and alleviates barrier dysfunction in psoriasis: results of a randomized controlled trial

Article / Letter to editor

open access

INTRODUCTION\nMETHODS\nRESULTS\nCONCLUSION\nThe epidermal inflammation associated with psoriasis drives skin barrier perturbations. The skin barrier is primarily located in stratum corneum (SC).... Show moreINTRODUCTION\nMETHODS\nRESULTS\nCONCLUSION\nThe epidermal inflammation associated with psoriasis drives skin barrier perturbations. The skin barrier is primarily located in stratum corneum (SC). Its function depends on the SC lipid matrix of which ceramides constitute important components. Changes in the ceramide profile directly correlate to barrier function. In this study, we characterized the dynamics of the barrier function and ceramide profile of psoriatic skin during anti-Interleukin-23 therapy with guselkumab.\nWe conducted a double-blind, randomized controlled trial in which 26 mild-to-severe plaque psoriasis patients were randomization 3:1 to 100mg guselkumab or placebo for 16 weeks and barrier dynamics monitored throughout. Barrier function was measured by trans-epidermal Water loss measurements. Untargeted ceramide profiling was performed using liquid chromatography-mass spectrometry after SC was harvested using tape-stripping.\nThe barrier function and ceramide profile of lesional skin normalized to that of controls during treatment with guselkumab, but not placebo. This resulted in significant differences compared to placebo at the end of treatment. Changes in the lesional ceramide profile during treatment correlated with barrier function and target lesion severity. Non-lesional skin remained similar throughout treatment.\nGuselkumab therapy restored the skin barrier in psoriasis. Concomitant correlations between skin barrier function, the ceramide profile and disease severity demonstrate their interdependency. Show less

Nădăban, A.; Frame, C.O.; El Yachioui, D.; Gooris, G.S.; Dalgliesh, R.M.; Malfois, M.; ... ; Bouwstra, J.A. 2024

The sphingosine and phytosphingosine ceramide ratio in lipid models forming the short periodicity phase: an experimental and molecular simulation study

Article / Letter to editor

open access

The lipids located in the outermost layer of the skin, the stratum corneum (SC), play a crucial role in maintaining the skin barrier function. The primary components of the SC lipid matrix are... Show moreThe lipids located in the outermost layer of the skin, the stratum corneum (SC), play a crucial role in maintaining the skin barrier function. The primary components of the SC lipid matrix are ceramides (CERs), cholesterol (CHOL), and free fatty acids (FFAs). They form two crystalline lamellar phases: the long periodicity phase (LPP) and the short periodicity phase (SPP). In inflammatory skin conditions like atopic dermatitis and psoriasis, there are changes in the SC CER composition, such as an increased concentration of a sphingosine-based CER (CER NS) and a reduced concentration of a phytosphingosine-based CER (CER NP). In the present study, a lipid model was created exclusively forming the SPP, to examine whether alterations in the CER NS:CER NP molar ratio would affect the lipid organization. Experimental data were combined with molecular dynamics simulations of lipid models containing CER NS:CER NP at ratios of 1:2 (mimicking a healthy SC ratio) and 2:1 (observed in inflammatory skin diseases), mixed with CHOL and lignoceric acid as the FFA. The experimental findings show that the acyl chains of CER NS and CER NP and the FFA are in close proximity within the SPP unit cell, indicating that CER NS and CER NP adopt a linear conformation, similarly as observed for the LPP. Both the experiments and simulations indicate that the lamellar organization is the same for the two CER NS:CER NP ratios while the SPP NS:NP 1:2 model had a slightly denser hydrogen bonding network than the SPP NS:NP 2:1 model. The simulations show that this might be attributed to intermolecular hydrogen bonding with the additional hydroxide group on the headgroup of CER NP compared with CER NS. Show less

Leiden University Scholarly Publications

Your Search

Enabled Filters

Sort Options

Refine Results

Resource Type

Availability

Creation Date

Faculty

Collection

Topic

Author

Language

Search results

Pages

Pages