2,371 results match your criteria: "Mathematical Institute[Affiliation]"

Background And Purpose:  Developmental dysplasia (DDH) and Legg-Calvé-Perthes disease (LCPD) are common indications for total hip arthroplasty (THA) at a young age, and may be associated with increased revision risk. We aimed to investigate the 10-year cumulative aseptic cup revision and overall revision risk of THA, and investigated whether these are increased compared with THA for primary osteoarthritis (OA) in patients below 55 years.

Methods:  All THAs (2007-2019) in patients under the age of 55 for the indications OA, DDH, and LCPD were extracted from the Dutch Arthroplasty register.

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Variations in plume activity reveal the dynamics of water-filled faults on Enceladus.

Nat Commun

August 2024

Laboratoire de Planétologie et Géosciences, UMR 6112, Nantes Université, Univ Angers, Le Mans Université, CNRS, Nantes, France.

After discovering a jet activity near the south pole of Saturn's moon Enceladus, the Cassini mission demonstrated the existence of a subsurface water ocean with a unique sampling opportunity through flybys. Diurnal variations in the observed brightness of the plume suggest a tidal control, although the existence and timing of two activity maxima seem to contradict stress analysis predictions. Here, we re-interpret the observed plume variability by combining a 3D global model of tidal deformation of the fractured ice shell with a 1D local model of transport processes within south-polar faults.

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Because of the low mutational burden and consequently, fewer potential neoantigens, children with acute myeloid leukemia (AML) are thought to have a T cell-depleted or 'cold' tumor microenvironment and may have a low likelihood of response to T cell-directed immunotherapies. Understanding the composition, phenotype, and spatial organization of T cells and other microenvironmental populations in the pediatric AML bone marrow (BM) is essential for informing future immunotherapeutic trials about targetable immune-evasion mechanisms specific to pediatric AML. Here, we conducted a multidimensional analysis of the tumor immune microenvironment in pediatric AML and non-leukemic controls.

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Article Synopsis
  • The 2022 global outbreak of mpox (formerly known as monkeypox) and its 2023 sporadic cases underscored the need for effective nonpharmaceutical interventions like case isolation.
  • A new modeling framework was created to analyze how long infected individuals remain infectious based on their viral load, revealing that viral shedding can vary significantly from 23 to 50 days.
  • The study found that while existing symptom-based isolation guidelines are generally effective, switching to a testing-based rule could minimize unnecessary isolation after individuals are no longer infectious.
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Exploring K values smaller than unity in remoxipride: A physiologically-based CNS model approach highlighting brain metabolism in drugs with passive blood-brain barrier transport.

Eur J Pharm Sci

December 2024

Division of Systems Pharmacology and Pharmacy, Predictive Pharmacology Group, Leiden Academic Centre of Drug Research, Leiden University, Gorlaeus Laboratories, Leiden, the Netherlands. Electronic address:

(aim): K values are crucial indicators of drug distribution into the brain, representing the steady-state relationship between unbound concentrations in plasma and in brain extracellular fluid (brainECF). K values < 1 are often interpreted as indicators of dominant active efflux transport processes at the blood-brain barrier (BBB). However, the potential impact of brain metabolism on this value is typically not addressed.

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In data assimilation, observations are fused with simulations to obtain an accurate estimate of the state and parameters for a given physical system. Combining data with a model, however, while accurately estimating uncertainty, is computationally expensive and infeasible to run in real-time for complex systems. Here, we present a novel particle filter methodology, the Deep Latent Space Particle filter or D-LSPF, that uses neural network-based surrogate models to overcome this computational challenge.

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A common problem in clinical trials is to test whether the effect of an explanatory variable on a response of interest is similar between two groups, for example, patient or treatment groups. In this regard, similarity is defined as equivalence up to a pre-specified threshold that denotes an acceptable deviation between the two groups. This issue is typically tackled by assessing if the explanatory variable's effect on the response is similar.

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Make the Most of Your Society Journal.

Bull Math Biol

August 2024

Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, OX2 6GG, UK.

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Plants are a paradigm for active shape control in response to stimuli. For instance, it is well known that a tilted plant will eventually straighten vertically, demonstrating the influence of both an external stimulus, gravity, and an internal stimulus, proprioception. These effects can be modulated when a potted plant is additionally rotated along the plant's axis, as in a rotating clinostat, leading to intricate shapes.

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Introduction: Treating older adults with chemotherapy remains a challenge, given their under-representation in clinical trials and the lack of robust treatment guidelines for this population. Moreover, older patients, especially those with frailty, have an increased risk of developing chemotherapy-related toxicity, resulting in a decreased quality of life (QoL), increased hospitalisations and high healthcare costs. Phase II trials have suggested that upfront dose reduction of chemotherapy can reduce toxicity rates while maintaining efficacy, leading to fewer treatment discontinuations and an improved QoL.

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Wave propagation in tailored metastructures consisting of elastic beams and rigid bodies.

Philos Trans A Math Phys Eng Sci

September 2024

Department of Mechanics, Faculty of Mechanical Engineering, Belgrade University, Kraljice Marije 16, Belgrade 11120, Serbia.

This paper presents a study of wave propagation through an infinite periodic structure that consists of elastic Timoshenko beams interconnected with rigid bodies. This is a generalized approach in which the beams are not coaxial and the centre of mass of each rigid body is placed away from the intersection of their neutral axes. An analytical approach is used by applying the transfer matrix method (TMM), along with the Floquet-Bloch theorem for elastic wave propagation.

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The trajectory of hematopoietic stem cell transplantation (HSCT) is often accompanied by physically disabling complications that impair physical performance of pediatric patients. However, knowledge about when impairments in physical performance arise and the factors contributing to these impairments is limited. Therefore, we conducted a retrospective analysis of physical performance 100 days post-HSCT in patients aged 3-18 years.

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The rapid development of vaccines against SARS-CoV-2 altered the course of the COVID-19 pandemic. In most countries, vaccinations were initially targeted at high-risk populations, including older individuals and healthcare workers. Now, despite substantial infection- and vaccine-induced immunity in host populations worldwide, waning immunity and the emergence of novel variants continue to cause significant waves of infection and disease.

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Infections lead to substantial morbidity during the treatment of acute lymphoblastic leukemia (ALL) in which the adaptive immune system is severely affected, leading to declining serum immunoglobulin levels. We performed a trial to investigate whether intravenous immunoglobulin (IVIG) prophylaxis in pediatric patients with ALL could prevent admissions for fever. This randomized controlled trial was a subtrial of the national Dutch multicenter ALL study.

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Blood Lipoproteins Shape the Phenotype and Lipid Content of Early Atherosclerotic Lesion Macrophages: A Dual-Structured Mathematical Model.

Bull Math Biol

August 2024

Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, Oxfordshire, OX2 6GG, UK.

Macrophages in atherosclerotic lesions exhibit a spectrum of behaviours or phenotypes. The phenotypic distribution of monocyte-derived macrophages (MDMs), its correlation with MDM lipid content, and relation to blood lipoprotein densities are not well understood. Of particular interest is the balance between low density lipoproteins (LDL) and high density lipoproteins (HDL), which carry bad and good cholesterol respectively.

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What is the dimension of a network? Here, we view it as the smallest dimension of Euclidean space into which nodes can be embedded so that pairwise distances accurately reflect the connectivity structure. We show that a recently proposed and extremely efficient algorithm for data clouds, based on computing first- and second-nearest neighbour distances, can be used as the basis of an approach for estimating the dimension of a network with weighted edges. We also show how the algorithm can be extended to unweighted networks when combined with spectral embedding.

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Article Synopsis
  • * This study develops a dynamic prediction model for 5-year overall survival, using data from 1965 patients and incorporating both baseline factors and time-varying events like local recurrence and new metastatic disease.
  • * Key findings reveal that certain baseline factors and disease-related variables significantly impact survival, emphasizing the value of updating predictions based on new information gathered during patient follow-up.
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We demonstrate that heterogeneity in the perceived risks associated with infection within host populations amplifies chances of superspreading during the crucial early stages of epidemics. Under this behavioural model, individuals less concerned about dangers from infection are more likely to be infected and attend larger sized (riskier) events, where we assume event sizes remain unchanged. For directly transmitted diseases such as COVID-19, this leads to infections being introduced at rates above the population prevalence to those events most conducive to superspreading.

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Global population health during the COVID-19 pandemic is poorly understood because of weak mortality monitoring in low- and middle-income countries. High-quality survey data on 765,180 individuals, representative of one-fourth of India's population, uncover patterns missed by incomplete vital statistics and disease surveillance. Compared to 2019, life expectancy at birth was 2.

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When should lockdown be implemented? Devising cost-effective strategies for managing epidemics amid vaccine uncertainty.

PLoS Comput Biol

July 2024

The Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, Mathematics Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom.

During an infectious disease outbreak, public health policy makers are tasked with strategically implementing interventions whilst balancing competing objectives. To provide a quantitative framework that can be used to guide these decisions, it is helpful to devise a clear and specific objective function that can be evaluated to determine the optimal outbreak response. In this study, we have developed a mathematical modelling framework representing outbreaks of a novel emerging pathogen for which non-pharmaceutical interventions (NPIs) are imposed or removed based on thresholds for hospital occupancy.

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Self-organization of individuals within large collectives occurs throughout biology. Mathematical models can help elucidate the individual-level mechanisms behind these dynamics, but analytical tractability often comes at the cost of biological intuition. Discrete models provide straightforward interpretations by tracking each individual yet can be computationally expensive.

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Soft matter physics of the ground beneath our feet.

Soft Matter

July 2024

Saint Anthony Falls Laboratory and Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN, USA.

The soft part of the Earth's surface - the ground beneath our feet - constitutes the basis for life and natural resources, yet a general physical understanding of the ground is still lacking. In this critical time of climate change, cross-pollination of scientific approaches is urgently needed to better understand the behavior of our planet's surface. The major topics in current research in this area cross different disciplines, spanning geosciences, and various aspects of engineering, material sciences, physics, chemistry, and biology.

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Article Synopsis
  • - The study explored the effectiveness of taurolidine-citrate(-heparin) lock solutions (TCHL) in preventing central-line-associated bloodstream infections (CLABSI) in pediatric oncology patients, with a trial conducted from 2020 to 2023.
  • - A total of 462 patients using central venous access devices were split into two groups: one using TCHL and the other using heparin-only locks (HL), with follow-ups for 90 days post-insertion.
  • - Results showed no significant difference in the incidence of CLABSI between the TCHL and HL groups, with slightly fewer infections in the TCHL group, but adverse events occurred more often in that group.
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Synaptic ribbons are the eponymous specializations of continuously active ribbon synapses. They are primarily composed of the RIBEYE protein that consists of a unique amino-terminal A-domain and carboxy-terminal B-domain that is largely identical to the ubiquitously expressed transcriptional regulator protein CtBP2. Both RIBEYE A-domain and RIBEYE B-domain are essential for the assembly of the synaptic ribbon, as shown by previous analyses of RIBEYE knockout and knockin mice and related investigations.

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Transient Amplification of Broken Symmetry in Elastic Snap-Through.

Phys Rev Lett

June 2024

Mathematical Institute, University of Oxford, Woodstock Rd, Oxford OX2 6GG, United Kingdom.

A snap-through bifurcation occurs when a bistable structure loses one of its stable states and moves rapidly to the remaining state. For example, a buckled arch with symmetrically clamped ends can snap between an inverted and a natural state as the ends are released. A standard linear stability analysis suggests that the arch becomes unstable to asymmetric perturbations.

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