bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micromechanics of fibrous scaffolds and their stiffness sensing by cells
Authors: Jyoti Mech Dhruba , Suhail Rizvi Mohd 
Published: January 2024

Abstract
Mechanical properties of the tissue engineering scaffolds are known to play a crucial role in cell response. Therefore, an understanding of the cell-scaffold interactions is of high importance. Here, we have utilized discrete fiber network model to quantitatively study the micromechanics of fibrous scaffolds with different fiber arrangements and cross-linking densities. We observe that localized forces on the scaffold result in its anisotropic deformation even for isotropic fiber arrangements. We also see an exponential decay of the displacement field with distance from the location of applied force. This nature of the decay allows us to estimate the characteristic length for force transmission in fibrous scaffolds. Furthermore, we also looked at the stiffness sensing of fibrous scaffolds by individual cells and its dependence on the cellular sensing mechanism. For this, we considered two conditions- stress-controlled, and strain-controlled application of forces by a cell. With fixed strain, we find that the stiffness sensed by a cell is proportional to the scaffold’s ‘macroscopic’ elastic modulus. However, under fixed stress application by the cell, the stiffness sensed by the cell also depends on the cell’s own stiffness. In fact, the stiffness values for the same scaffold sensed by the stiff and soft cells can differ from each other by an order of magnitude. The insights from this work will help in designing tissue engineering scaffolds for applications where mechanical stimuli are a critical factor.
Vaccination, asymptomatics and public health information in COVID-19
Authors: Grinfeld Michael , Mulheran Paul A 
Published: January 2024

Abstract
The dynamics of the COVID-19 pandemic is greatly influenced by vaccine quality, as well as by vaccination rates and the behaviour of infected individuals, both of which reflect public health policies. We develop a model for the dynamics of relevant cohorts within a fixed population, taking extreme care to model the reduced social contact of infected individuals in a rigorous self-consistent manner. The basic reproduction number R
0 is then derived in terms of the parameters of the model. Analysis of R
0 reveals two interesting possibilities, both of which are plausible based on known characteristics of COVID-19. Firstly, if the population in general moderates social contact, while infected individuals who display clinical symptoms tend not to isolate, then increased vaccination can drive the epidemic towards a disease-free equilibrium (DFE). However, if the reverse is true, then increased vaccination can destabilise the DFE and yield an endemic state. This surprising result is due to the fact that the vaccines are leaky, and can lead to an increase in asymptomatic individuals who unknowingly spread the disease. Therefore, this work shows that public policy regarding the monitoring and release of health data should be combined judiciously with modeling-informed vaccination policy to control COVID-19.
Global density equations for a population of actively switching particles
Authors: Bressloff Paul C 
Published: January 2024

Abstract
There are many processes in cell biology that can be modelled in terms of an actively switching particle. The continuous degrees of freedom of the particle evolve according to a hybrid stochastic differential equation whose drift term depends on a discrete internal or environmental state that switches according to a continuous time Markov chain. Examples include Brownian motion in a randomly switching environment, membrane voltage fluctuations in neurons, protein synthesis in gene networks, bacterial run-and-tumble motion, and motor-driven intracellular transport. In this paper we derive generalized Dean–Kawasaki (DK) equations for a population of actively switching particles, either independently switching or subject to a common randomly switching environment. In the case of a random environment, we show that the global particle density evolves according to a hybrid DK equation. Averaging with respect to the Gaussian noise processes in the absence of particle interactions yields a hybrid partial differential equation for the one-particle density. We use this to show how a randomly switching environment induces statistical correlations between the particles. We also discuss methods for handling the moment closure problem for interacting particles, including dynamical density functional theory and mean field theory. We then develop the analogous constructions for independently switching particles. In order to derive a DK equation, we introduce a discrete set of global densities that are indexed by the single-particle internal states, and take expectations with respect to the switching process. However, the resulting DK equation is no longer closed when particle interactions are included. We conclude by deriving Martin–Siggia–Rose–Janssen–de Dominicis path integrals for the global density equations in the absence of interactions, and relate this to recent field theoretic studies of Brownian gases and run-and-tumble particles.
Circumventing data imbalance in magnetic ground state data for magnetic moment predictions
Authors: Sanspeur Rohan Yuri , Kitchin John R 
Published: January 2024

Abstract
Magnetic materials play a crucial role in the transition to more sustainable forms of energy and electric vehicles. There is an anticipated shortage in magnetic materials in the future, and as a result there is an urgent need to discover and design new magnetic materials. Computational magnetic material design using density functional theory is daunting because of the challenge in identifying magnetic ground states from a combinatorially large set of possibilities. Machine learning offers a path forward by enabling efficient surrogate models that can more readily enumerate these states, but there is a dearth of training data available, and what is available tends to be imbalanced with too much non-magnetic data. In this work we show that the discrete and previously tackled data imbalance that exists at the level of the magnetic ordering leads to an imbalanced continuous distribution with many zeros when the data is unraveled at the atomic magnetic moment level, which subsequently leads to models with low accuracy for magnetic properties. We mitigate this by using a two-part model framework. Our scheme is able to classify atoms into magnetic and non-magnetic with an F1 score and Matthew’s correlation coefficient (MCC) of ~91% and then to provide an implicit embedding representation that maps directly onto the magnitude of the magnetic moment with a mean absolute error of 0.1

μ

B

. Beyond screening for new magnetic materials, we demonstrate an additional practical use case of our scheme: the provision of good initial guesses for magnetic moments in first-principles electronic relaxations. Such initialization is shown to lead to faster convergence to configurations that lie closer to the ground state.
Preventing Bacterial Contamination of Breast Implants Using Infection Mitigation Techniques: An In Vitro Study
Authors: Chow Oliver , Hu Helen , Lajevardi Sepehr Seyed , Deva Anand K , Atkinson Richard L 
Published: January 2024

Abstract

Background
Bacterial contamination of implants has been linked to biofilm formation and subsequent infection, capsular contracture, and breast implant–associated anaplastic large cell lymphoma. Reducing contamination during implant insertion should therefore reduce biofilm formation disease sequelae.

Objectives
The aim of this study was to compare levels of contamination between preventative techniques.

Methods
A model to simulate the passage of implants through a skin incision was designed that utilized a sterile textured polyvinyl plastic sheet contaminated with Staphylococcus epidermidis. In the first stage of the polyvinyl contamination model, implants were subject to infection-mitigation techniques and passed through the incision, then placed onto horse blood agar plates and incubated for 24 hours. In the second stage of the study the same contamination was applied to human abdominal wall specimens. A 5 cm incision was made through skin and fat, then implants were passed through and levels of contamination were measured as described.

Results
Smooth implants grew a mean of 95 colony-forming units (CFUs; approximately 1 CFU/cm2) and textured implants grew 86 CFUs (also approximately 1 CFU/cm2). CFU counts were analyzed by the Mann-Whitney U-test which showed no significant difference between implant types (P &lt; .05); independent-sample t-tests showed a significant difference. The dependent-variable techniques were then compared as groups by one-way analysis of variance, which also showed a significant reduction compared with the control group (P &lt; .01).

Conclusions
This in vitro study has shown the effectiveness of antiseptic rinse and skin/implant barrier techniques for reducing bacterial contamination of breast implants at the time of insertion.
The Superior Effect of Radiofrequency With Targeted Ultrasound for Facial Rejuvenation by Inducing Hyaluronic Acid Synthesis: A Pilot Preclinical Study
Authors: Duncan Diane , Bernardy Jan , Hodkovicova Nikola , Masek Josef , Prochazkova Marketa , Jarosova Rea 
Published: January 2024

Abstract

Background
The level of dermal hyaluronic acid (HA) can be depleted by 75% at age 70. HA provides dermal hydration, volume, and thickness, making it a major component of the extracellular matrix. Restoration of dermal and epidermal HA can be achieved by combining radiofrequency (RF) energy and targeted ultrasound (TUS). The monopolar RF generates heat, with the TUS stimulating HA production. The heat induces a regenerative response in the skin, increasing the fibroblast activity and producing various extracellular matrix compounds, including HA.

Objectives
To investigate the effect of the simultaneous application of RF + TUS or RF + US on the stimulation of HA production.

Methods
Twelve animals underwent 4 treatments. Six were treated with transcutaneous RF + TUS and 6 with the combination RF + US. The opposite untreated side served as a control. Punch biopsies of the skin were taken at baseline, immediately posttreatment, 1 month, and 2 months posttreatment. The tissue was evaluated with real-time quantitative polymerase chain reaction (RT-qPCR), matrix-assisted laser desorption (MALDI) and time of flight (TOF), and confocal microscopy.

Results
The RT-qPCR focused on assessing the production of has1 and has2, enzymes responsible for HA synthesis. RT-qPCR results of the RF + TUS group revealed a +98% and +45% increase in hyaluronic synthetase (HAS) 1 and HAS2 production after the treatments, respectively. The MALDI–TOF revealed a +224% increase in measured HA 2 months after the treatments. The changes were also visible in the confocal microscopy. The control group showed no significant (P &gt; .05) results in either of the evaluation methods.

Conclusions
Concurrent application of RF and TUS significantly enhances the natural regenerative processes in skin tissue.

Level of Evidence: 5
The relationship between genetic diversity, function, and stability in marine foundation species
Authors: Konefal Anastasia , Kirkland Amanda , Gilpin Rebecca , Wyssmann Kathryn , Anthony Nicola M , Cebrian Just , Cox T Erin 
Published: January 2024

Abstract
Seagrasses, corals, marsh plants, kelps, and mangroves support valuable coastal ecosystems but are threatened by environmental stressors. The need to manage these foundation taxa has spurred more than a decade of study on the relationship between genetic diversity and function or stability. We synthesized this literature base (129 relevant publications) and found more reported instances of neutral to positive relationships between genetic diversity and function than negative. However, much of the scientific understanding is based on the response of three genera and from unreplicated observational studies that correlate genetic diversity to measured response variables. When a disturbance was present, the studies often lacked controls or baseline data. Only 5.5% of the studies robustly tested for stability. These shortcomings preclude a rigorous evaluation of whether more genetically diverse foundation populations increase stability and hinder the use of genetics-based conservation strategies. Future studies should be focused on diverse species and ecosystem-level impacts using manipulative designs.
Molecular analyses support revision of species diversity of the moss genus Bryum in Antarctica
Authors: Cannone N , Vanetti I , Convey P , Sancho L G , Zaccara S 
Published: January 2024

Abstract
Bryum is a moss genus that is widely distributed across the planet. Many of its species are characterized by large phenotypic and morphological plasticity, generating uncertainty in species identification exclusively based on morphological characteristics. In Antarctica, the extreme and harsh environmental conditions are further likely to promote intra-specific morphological variation, leading to complexity in the taxonomic attribution of Bryum species. In this study, we apply molecular phylogenetic analyses to assist in developing accurate species identification of B. pseudotriquetrum and two other relatively abundant Bryum species (B. archangelicum and B. pallescens) currently reported as Antarctic species.
A total of 51 Bryum samples collected in Antarctica (22) and from all other continents (29) were sequenced for ITS nrDNA and rps4 cpDNA regions, using markers widely used in moss phylogenetic studies. Phylogenetic trees were constructed including ITS (23) and rps4 (34) sequences representing the three more frequent of the seven Bryum species currently reported from Antarctica as well as several other Bryum species and related genera, incorporating all sequence data available in the literature and accessible databases. The molecular analyses provide strong support for a match between morphological and molecular attribution of specimens identified as B. pseudotriquetrum. The data also provide evidence of currently unrecognized Bryum diversity in Antarctica, with the identification of one individual of B. uliginosum. However, the analyses suggest that all Antarctic specimens currently assigned to other Bryum species are morphological variants of B. pseudotriquetrum. The integration of molecular and morphological analyses supports the presence of B. pseudotriquetrum as the most widely distributed species of the genus in Antarctica and of B. uliginosum with a much more restricted distribution (South Sandwich Islands). Our data suggest that further investigation is required of B. archangelicum and B. pallescens in other continents globally, as the identity of none of the herbarium specimens examined in this study could be confirmed with molecular data.
Dissociation of reading and naming in ventral occipitotemporal cortex
Authors: Woolnough Oscar , Tandon Nitin 
Published: January 2024

Abstract
Lesions in the language-dominant ventral occipitotemporal cortex (vOTC) can result in selective impairment of either reading or naming, resulting in alexia or anomia. Yet, functional imaging studies that show differential activation for naming and reading do not reveal activity exclusively tuned to one of these inputs.
To resolve this dissonance in the functional architecture of the vOTC, we used focused stimulation to the vOTC in 49 adult patients during reading and naming, and generated a population-level, probabilistic map to evaluate if reading and naming are clearly dissociable within individuals. Language mapping (50 Hz, 2829 stimulations) was performed during passage reading (216 positive sites) and visual naming (304 positive sites).
Within the vOTC, we isolated sites that selectively disrupted reading (24 sites in 11 patients) or naming (27 sites in 12 patients), and those that disrupted both processes (75 sites in 21 patients). The anteromedial vOTC had a higher probability of producing naming disruption, while posterolateral regions resulted in greater reading-specific disruption. Between them lay a multi-modal region where stimulation disrupted both reading and naming.
This work provides a comprehensive view of vOTC organization—the existence of a heteromodal cortex critical to both reading and naming, along with a causally dissociable unimodal naming cortex, and a reading-specific visual word form area in the vOTC. Their distinct roles as associative regions may thus relate to their connectivity within the broader language network that is disrupted by stimulation, more than to highly selective tuning properties. Our work also implies that pre-surgical mapping of both reading and naming is essential for patients requiring vOTC resections, as these functions are not co-localized, and such mapping may prevent the occurrence of unexpected deficits.
Trophic niche segregation in a guild of top predators within the Mediterranean Basin
Authors: Ramellini Samuele , Crepet Emanuele , Lapadula Stefano , Romano Andrea 
Published: January 2024

Abstract
Niche theory predicts that closely related and ecologically similar species with overlapping distribution ranges can coexist through resource partitioning that limits interspecific competition. However, studies examining the mechanisms promoting coexistence of top predators at a large geographical scale are still scant. Here, we describe the foraging ecology of 3 sympatric owl species (Northern long-eared owl [Asio otus], Tawny owl [Strix aluco], Eurasian eagle owl [Bubo bubo]) in the Mediterranean Basin. We review 160 studies reporting diet information (212,236 vertebrate preys) and investigate among-species differences in diet metrics (diversity, evenness, prey size, and proportion of mammals) and their variation along geographical and environmental gradients. Moreover, we test whether diet metrics differ in presence or absence of the other predators. All the 3 species mainly rely on small mammals, but they significantly differ in diet metrics. The smallest predator (i.e., long-eared owl) shows a higher level of specialism on small mammals (highest proportion but lowest diversity of mammals in the diet) compared to the larger ones. In addition, mean prey size significantly increases with predator body size (long-eared owl &lt; tawny owl &lt; eagle owl). Finally, interspecific competition results in an increase of diet diversity and evenness in the long-eared owl, and species’ diet also varies in response to environmental factors. The 3 species thus segregate along several dietary niche axes over a large spatial scale and according to both morphological characteristics (i.e., body size) and environmental variables. Such dietary niche segregation may adaptively buffer interspecific competition costs, ultimately allowing coexistence.
Severe diastolic dysfunction as a clue to the cause of stroke: a case report
Authors: Maalouf Maya , Mandel William J , Pollick Charles 
Published: January 2024

Abstract

Background
The echocardiographic determination of cardiac causes of stroke focuses on the presence of left ventricular thrombus, valvular vegetations, and patent foramen ovale. Transoesophageal echocardiogram (TEE) is indicated when the transthoracic echocardiogram (TTE) is inconclusive or when there is clinical suspicion of cardiac causes that may have been missed by TTE. The presence of severe diastolic dysfunction on TTE in the absence of any other cardiac abnormality or cardiac history is not usually considered a clue to the cause of stroke.

Case summary
This is a case of a 52-year-old woman who presented with a stroke. Transthoracic echocardiogram was inconclusive for source of embolus. Transoesophageal echocardiogram revealed left atrial appendage (LAA) thrombus and severely hypokinetic LAA, despite the patient being in normal sinus rhythm (NSR). Retrospective analysis of diastolic function on the prior TTE revealed severe restrictive diastolic dysfunction with evidence of elevated left ventricular end-diastolic pressure. While technetium pyrophosphate scan was negative, magnetic resonance imaging was consistent with cardiac amyloid and further testing revealed multiple myeloma as the cause of the amyloid light chain amyloidosis. This case highlights the importance of scrutinizing diastolic function in patients with a source of embolus and careful assessment for LAA thrombus on TEE, despite NSR.

Discussion
We present a patient with stroke with inconclusive TTE findings and eventual diagnosis of restrictive cardiomyopathy secondary to cardiac amyloidosis from an undiagnosed multiple myeloma. Severe restrictive diastolic function on TTE may be a clue to the discovery of LAA thrombus on TEE.
Protected high risk percutaneous coronary intervention—Impella 5.0 as a single-access technique: a case report
Authors: Medina Marta , Wenzel Philip , Fathallah Bilel , Ruf Tobias , Oezkur Mehmet 
Published: January 2024

AbstractBackgroundPatients requiring coronary intervention after acute myocardial infarction, with decompensated heart failure and multiple co-morbidities, present a challenging clinical scenario. Addressing such high-risk cases has been a marked increase in the simultaneous support using microaxial flow pump devices, providing a crucial haemodynamic support during procedures.Case summaryWe report the case of a 58-year-old man, with a non-ST-segment elevation myocardial infarction in the context of a peripheral vascular surgery. Echocardiography revealed severely reduced left ventricular function and cardiac magnetic resonance imaging demonstrated transmural scars in all but left anterior descending artery area. The patient was of extreme high surgical risk due to the multiple co-morbidities, acute decompensation heart failure, and peripheral artery disease, and, therefore, the heart team preferred protected percutaneous coronary intervention (PCI) over coronary artery bypass graft for revascularization. The peripheral artery disease included severely calcified ascending aorta, occlusions of both femoral arteries, the left subclavian artery, and the right radial artery. Taken together, the heart team agreed on a hybrid approach with surgical implantation of Impella 5.0 via the left subclavian artery, by a single-access technique. Following the intervention procedure, haemostasis of the vascular prosthesis was achieved by an angio-seal technique without complications. The patient recovered satisfactorily, with improved left ventricular function, and discharged 10 days post-procedure.DiscussionThe single-access high-risk PCI technique offers a standardized approach for microaxial flow pump devices such as Impella 5.0 and PCI. The subclavian artery as a single-access route for high-risk PCI has demonstrated safety and efficacy.