bluuebunny/crossref_metadata_2025 huggingface dataset:
Core–shell cobalt-iron@N-doped carbon: A high-performance cathode material for lithium–sulfur batteries
Authors: Zhang Xiuling , Zhang Jiaying , Feng Yun , Shen Linkun , Cao Xiangyu , Liu Lu , Yan Juanzhi
Published: October 2024

Lithium–sulfur batteries hold great promise as energy storage systems, but the shuttle effect of lithium polysulfides (LiPS) and large volume variation limit their capacity and cycle life. We have developed CoFe alloy wrapped in N-doped porous carbon spheres (e-CF@NC) with a core–shell structure through simple copolymerization and pyrolysis. The nitrogen-doped porous carbon shell provides electron and ion transport channels and more active sites for electrolyte ion adsorption. The high chemically stable carbon can limit the segregation of polysulfides, further improving the battery cycling stability. Besides, the inside CoFe alloy particles catalyze the conversion between LiPS and Li2S, speeding up reaction kinetics and reducing solvation of active sites. Consequently, lithium–sulfur batteries with e-CF@NC-2 as the cathode display a high initial specific capacity of 1146 mA h g−1 at 0.1 C, excellent rate performance (891 mA h g−1 at 1 C, 741 mA h g−1 at 2 C), and satisfied cycle stability (average capacity decay rate of 0.033% per cycle at 1 C for 300 cycles), demonstrating significant application potential.
Frequency-reconfigurable liquid crystal metasurface array
Authors: Zhang Guo-Qi , Zhang Lei , Zhang Hai-Feng
Published: October 2024

In this paper, a frequency-reconfigurable metasurface (MS) circularly polarized antenna array (CPAA) based on liquid crystal (LC) is presented. The antenna features a multilayer structure. Design of the MS circularly polarized antenna unit using the characteristic mode analysis method, the combination of MS structure, temperature-controlled LC, and sequential feed network not only enhances the impedance bandwidth (IBW), axial ratio bandwidth (ARBW), and gain. By adjusting the temperature to change the relative dielectric constant of the LC, further frequency reconfigurability of the CPAA is achieved. Under different temperature control settings, the effective IBW and ARBW of the antenna can be shifted from 39.0% (4.51–6.70 GHz) to 40.3% (4.61–6.94 GHz), while the peak gain moves from 11.59 dBi at 5.31 GHz to 11.71 dBi at 5.41 GHz. The results demonstrate that the proposed MS CPAA offers advantages of wide bandwidth, high gain, low profile, and frequency reconfigurability.
Careers by the numbers
Authors: Fitzgerald Richard J.
Published: October 2024

What’s the next career step for new recipients of physics bachelor’s degrees? Of physics PhDs? Data give some insights.
The
ivory
lncRNA regulates seasonal color patterns in buckeye butterflies
Authors: Fandino Richard A. , Brady Noah K. , Chatterjee Martik , McDonald Jeanne M. C. , Livraghi Luca , van der Burg Karin R. L. , Mazo-Vargas Anyi , Markenscoff-Papadimitriou Eirene , Reed Robert D.
Published: October 2024

Long noncoding RNAs (lncRNAs) are transcribed elements increasingly recognized for their roles in regulating gene expression. Thus far, however, we have little understanding of how lncRNAs contribute to evolution and adaptation. Here, we show that a conserved lncRNA,
ivory
, is an important color patterning gene in the buckeye butterfly
Junonia coenia
.
ivory
overlaps with
cortex
, a locus linked to multiple cases of crypsis and mimicry in Lepidoptera. Along with a companion paper by Livraghi et al., we argue that
ivory
, not
cortex
, is the color pattern gene of interest at this locus. In
J. coenia
, a cluster of
cis
-regulatory elements (CREs) in the first intron of
ivory
are genetically associated with natural variation in seasonal color pattern plasticity, and targeted deletions of these CREs phenocopy seasonal phenotypes. Deletions of different
ivory
CREs produce other distinct phenotypes as well, including loss of melanic eyespot rings, and positive and negative changes in overall wing pigmentation. We show that the color pattern transcription factors Spineless, Bric-a-brac, and Ftz-f1 bind to the
ivory
promoter during wing pattern development, suggesting that they directly regulate
ivory
. This case study demonstrates how
cis
-regulation of a single noncoding RNA can exert diverse and nuanced effects on the evolution and development of color patterns, including modulating seasonally plastic color patterns.
Differences in cognitive function at 18 y of age explain the association between low education and early dementia risk
Authors: Bratsberg Bernt , Fjell Anders M. , Rogeberg Ole J. , Skirbekk Vegard F. , Walhovd Kristine B.
Published: October 2024

Major initiatives attempt to prevent dementia by targeting modifiable risk factors. Low education is frequently pointed to, due to its relationship with dementia. Impact of education is difficult to assess, however, because of associations with multiple other factors, requiring large population-representative samples to tease the relationships apart. We studied 207,814 Norwegian men born between 1950 and 1959 who underwent compulsory cognitive testing during military conscription as young adults, to systematically test associations of education, cognition, and other important factors. Participants were grouped into five education levels and seven cognitive levels. A total of 1,521 were diagnosed with dementia between ages 60 and 69 y. While having compulsory education only was associated with increased risk (Hazard ratio [HR] = 1.37, CI: 1.17 to 1.60), this association was markedly attenuated when controlling for cognitive test scores (HR = 1.08, CI: 0.91 to 1.28). In contrast, low cognitive score was associated with double risk of later diagnosis, even when controlling for education (HR = 2.00, CI: 1.65 to 2.42). This relationship survived controlling for early-life socioeconomic status and replicated within pairs of brothers. This suggests that genetic and environmental factors shared within families, e.g., common genetics, parental education, socioeconomic status, or other shared experiences, cannot account for the association. Rather, independent, nonfamilial factors are more important. In contrast, within-family factors accounted for the relationship between low education and diagnosis risk. In conclusion, implementing measures to increase cognitive function in childhood and adolescence appears to be a more promising strategy for reducing dementia burden.
More than tough luck
Authors: Alhmoud Zeina
Published: October 2024

Applied Cognitive Linguistics (ACL, henceforth) offers a vision of language closely tied to our experiences and
views of the world, showing great promise for foreign language teaching and learning. Building upon this meaning-centered
perspective, this paper discusses an interventional, quasi-experimental study assessing the effectiveness of incorporating
animated images into materials for teaching comparative constructions in L2 Spanish. Conducted in three phases with varying
participation rates (69 students in the first, 18 in the second, and 27 in the third), the study faced numerous factors that
hindered data collection process and thereby influenced the results. Although the findings were not statistically significant,
they suggest a slight improvement in post-test performance in both the experimental and comparison groups. While the potential of
ACL in second language teaching and learning is undeniable, so are the challenges faced in L2 classrooms. This underscores the
need for further empirical research to bridge the gap between theoretical principles and their practical implementation in real
classroom settings.
Energy–dependent femtosecond LIPSS on germanium and application in explosives sensing
Authors: Rathod Jagannath , Moram Sree Satya Bharati , Soma Venugopal Rao
Published: October 2024

In this study, we fabricated laser-induced periodic surface structures (LIPSS) on a germanium surface through laser ablation in air using axicon and femtosecond (fs) pulses. This novel approach permitted the nanoscale material processing outcome refinement via an fs Bessel beam. Our investigations aimed at systematically understanding the formation of periodic structures under various experimental conditions, such as (i) different pulse energies ranging from 50 µJ to 1000 µJ at a constant scan speed and (ii) constant energy with different scan speeds (0.1–3 mm s−1). By adjusting the fluences and scan speeds, we were able to identify the parametric space and alter the periodicity of the low-spatial frequency LIPSS and high-spatial frequency LIPSS on germanium, which were analyzed using field emission scanning electron microscopy. An optimal LIPSS formation over a large area of germanium was achieved at an input energy of 250 µJ and a scan speed of 0.75 mm s−1. Additionally, we measured the contact angles of the Ge nanostructures (GeNSs) to demonstrate their hydrophobic nature and non-wetting properties, providing insights into the behavior of LIPSS. Subsequently, the GeNSs were coated with a ∼15 nm thick gold (Au) film using a thermal deposition method. Utilizing these, the surface-enhanced Raman spectroscopy (SERS) technique detected diverse analytes, such as tetryl (an explosive) at a concentration of 50 µM and thiram (a pesticide) at 500 nM. The SERS enhancement factors for tetryl and thiram molecules on GeNSs coated with a 15 nm-thick Au layer were determined to be 2.5 × 104 and 4.2 × 105, respectively.
Revealing the flashover mechanism of EP/GF composite insulation under DC combined harmonic voltage
Authors: Liu Ji , Zhang Longfei , Wei Yaoxin , Wang Pengfei , Zhang Jian , Li Zhen
Published: October 2024

In ultra–high voltage converter stations, the phenomenon of flashover along the outer insulation of dry hollow reactors made of epoxy (EP) /glass fiber (GF) composites poses a potential threat to the stability of the power system. To enhance its flashover performance under varying complex conditions, it is necessary to conduct in–depth research on the flashover mechanism of this material under different voltage forms. This study conducted tests on the flashover voltage, surface space charge distribution, and partial discharge (PD) parameters under varying AC–DC ratios and AC frequencies, and exploring their relationships. The results show that the DC content in the AC–DC ratio decreases, the flashover voltage decreases, the apparent total discharge of PDs increases, and the maximum surface space charge density decreases. The main influencing factor is the increase in the number of seed charges involved in gas ionization. Increasing the AC frequency, the flashover voltage decreases, the apparent total discharge increases significantly, and the surface charge density remains basically unchanged. The main reason is that the change in the number of alternating cycles further increases the number of seed charges. This study reveals the flashover mechanism of EP/GF composites under different voltage forms, which provides theoretical support for subsequent material modification.
Clustered ultra-small iron oxide nanoparticles as potential T1/T2 dual–modal magnetic resonance imaging contrast agents and application to tumor model
Authors: Liu Ying , Ho Son Long , Tegafaw Tirusew , Zhao Dejun , Ahmad Mohammad Yaseen , Ali Al Saidi Abdullah Khamis , Cha Hyunsil , Lee Sangyeol , Lee Hansol , Kim Seungho , Han Mun , Chae Kwon Seok , Chang Yongmin , Lee Gang Ho
Published: October 2024

Many studies have been conducted on the use of ultra–small iron oxide nanoparticles (USIONs) (d < 3 nm) as potential positive magnetic resonance imaging (MRI)–contrast agents (CAs); however, there is dearth of research on clustered USIONs. In this study, nearly monodispersed clustered USIONs were synthesized using a simple two–step one–pot polyol method. First, USIONs (d = 2.7 nm) were synthesized, and clustered USIONs (d = 27.9 nm) were subsequently synthesized through multiple cross–linking of USIONs with poly(acrylic acid–co–maleic acid) (PAAMA) polymers with many–COOH groups. The clustered PAAMA–USIONs exhibited very weak ferromagnetism owing to the magnetic interaction between superparamagnetic USIONs; this was evidenced by their appreciable r
1 = 3.9 s‒1 mM‒1 and high r
2/r
1 ratio of 14.6. Their ability to function as a dual–modal T
1/T
2 MRI–CA in T
1–weighted MRI was demonstrated when they simultaneously exhibited positive and negative contrasts in T
1–weighted MRI of tumor model mice after intravenous injection. They displayed positive contrasts at the kidneys, bladder, heart, and aorta and negative contrasts at the liver and tumor.
Effect of parity–time symmetry operation on entanglement distribution in two parallel Heisenberg spin chains
Authors: Wang Qiong , Cheng Li-Zheng , He Zhi
Published: October 2024

The effect of the parity–time (

PT

) symmetry operation on the entanglement transfer in two parallel Heisenberg spin chains is investigated. We give two schemes, i.e. pre- and post-

PT

symmetric operations, to demonstrate the performance of the

PT

symmetric operation on the entanglement dynamics of two qubits. In our investigation, we find that the effect of pre-

PT

symmetric operation schemes on the protection of entanglement of two qubits in the case of double spin chains is superior to that of the single spin chain case. Conversely, the effect of the post-

PT

symmetric operation scheme on the protection of entanglement of two qubits in the single spin chain case is better than that in the double spin chain case.
Tensile test and finite element simulation of coarse-grained thin aluminium sheets
Authors: Szlancsik A , Varga D
Published: October 2024

The aim of this work was to investigate the ability of finite element simulations applied to specimens containing only a few grains for tensile testing. For this purpose, two different finite element models were created: one with individual grains with individual flow curves generated by viscoplastic self-consistent (VPSC) calculations and one with uniform material properties throughout the cross-section of the sample. In comparison of the two models with experimental tensile tests, the following conclusions can be yielded. The measurement and the simulation with individual grains have the same deformation shape. Also, the mechanical properties (yield strength, tensile strength and elongation at break) were within 10% error. However, if the measurement results were compared to the simulation with homogeneous material, it showed an error up to 53%. Therefore, it can be stated that the tensile tests of these types of specimens can be simulated, but only if the grains are modelled individually.
Unidirectional fibre reinforcement of syntactic metal foams
Authors: Szovák B , Maróti J E , Kemény A , Orbulov I N
Published: October 2024

Metal matrix syntactic foams are porous structures where the porosity is formed by introducing a porous filler material into the metal matrix. They have low density and absorb significant energy during compression but cannot withstand tensile stress. The main goal of this study was to apply unidirectional fibre reinforcement to syntactic metal foams. Therefore, a lightweight double-composite structure that can be utilised against tensile load and has advantageous properties during compression was created. Copper-nickel coated carbon fibre bundles were used as unidirectional long fibre reinforcement, lightweight expanded clay aggregate particles as filler material and Al99.5 aluminium as matrix material. The samples were created with vacuum infiltration and formed into cylindrical tensile specimens. Quasi-static tensile tests were carried out on the specimens and fibre trusses, and quasi-static compression was applied on specimens in the parallel and perpendicular direction to the unidirectional fibre truss.
Physical Simulations of the Tool Degradation in Friction Stir Welding
Authors: El Imane Djimaoui Nour , Adonyi Yoni , De Backer Jeroen , Kovács Árpád , Kuzsella László , Mertinger Valéria
Published: October 2024

The present investigation is part of a comprehensive failure study of friction stir welding (FSW) tools, where experimental non-destructive and destructive evaluations are combined with analytical- and physical- simulations of tool wear mechanisms. This paper focuses on the research methodology and the primary results of Gleeble simulations of thermal- and mechanical-cycle effects on an H13 steel material widely used for FSW tools for welding aluminum and magnesium alloys.
Investigation of Co-Cr alloy layer prepared by laser metal deposition
Authors: Hareancz F , Juhász G , Buza G , Fábián R E , Vida Á
Published: October 2024

Additive technologies are commonly used for component production and repair. Laser metal deposition is a type of additive technology that can create new bodies or add new components to existing parts. This technology enables continuous modification of the chemical and material properties of the deposited layer to suit the intended purpose. The alloying powder is dissolved and mixed in a small volume molten pool during laser deposition. The laser cladding process is known for its rapid heating and cooling rates. This can result in partial or non-existent dissolution of powder particles in the molten pool, or the formation of non-equilibrium microstructures that cannot be achieved through conventional metallurgical processes. As a result, this method can be used to create materials with unique combinations of properties. In this study, a Co-Cr coating layer was applied to a structural steel base plate. The parameters combination was generated using Taguchi’s experimental design. The relationship between the parameters and the properties of the prepared coating was evaluated using the Taguchi method.
Development of multifunctional H2S-releasing gold nanoparticles for chronic wound treatment
Authors: Nguyen Van Phong , Nguyen Huyen Thanh Anh , Trang Le Ngoc Thuy , Nguyen Ngoc Hoi , Nguyen Dai Hai , Tran Dieu Linh
Published: October 2024

Chronic wounds, characterized by prolonged inflammation, require new therapies to improve healing. Hydrogen sulfide (H2S), a key neurotransmitter, supports critical factors in wound healing but is often deficient in chronic wounds. Despite its potential, the toxicity of direct H2S delivery and the unsustainable release from current systems hinder its therapeutic use. This study introduces H2S-releasing gold nanoparticles synthesized by reducing chloroauric acid (HAuCl4) with diallyl trisulfides (DATS), a naturally derived H2S donor. These nanoparticles are hypothesized to be biocompatible and multifunctional, combining H2S release with the beneficial properties of gold. Results show that DATS does not impair H2S release, and higher DATS concentrations enhance H2S output. The sustained H2S release promotes endothelial cell proliferation, migration, and angiogenesis while retaining the antimicrobial properties of gold nanoparticles, making this material promising for chronic wound treatment.
Advanced artificial intelligence framework for T classification of TNM lung cancer in 18FDG-PET/CT imaging
Authors: Trabelsi Mariem , Romdhane Hamida , Ben Salem Lotfi , Ben-Sellem Dorra
Published: October 2024

The integration of artificial intelligence (AI) into lung cancer management offers immense potential to revolutionize diagnostic and treatment strategies. The aim is to develop a resilient AI framework capable of two critical tasks: firstly, achieving accurate and automated segmentation of lung tumors and secondly, facilitating the T classification of lung cancer according to the ninth edition of TNM staging 2024 based on PET/CT imaging. This study presents a robust AI framework for the automated segmentation of lung tumors and T classification of lung cancer using PET/CT imaging. The database includes axial DICOM CT and 18FDG-PET/CT images. A modified ResNet-50 model was employed for segmentation, achieving high precision and specificity. Reconstructed 3D models of segmented slices enhance tumor boundary visualization, which is essential for treatment planning. The Pulmonary Toolkit facilitated lobe segmentation, providing critical diagnostic insights. Additionally, the segmented images were used as input for the T classification using a CNN ResNet-50 model. Our classification model demonstrated excellent performance, particularly for T1a, T2a, T2b, T3 and T4 tumors, with high precision, F1 scores, and specificity. The T stage is particularly relevant in lung cancer as it determines treatment approaches (surgery, chemotherapy and radiation therapy or supportive care) and prognosis assessment. In fact, for Tis-T2, each increase of one centimeter in tumor size results in a worse prognosis. For locally advanced tumors (T3-T4) and regardless of size, the prognosis is poorer. This AI framework marks a significant advancement in the automation of lung cancer diagnosis and staging, promising improved patient outcomes.
Bio-mechanical analysis of porous Ti-6Al-4V scaffold: a comprehensive review on unit cell structures in orthopaedic application
Authors: Deshmukh Sachin , Chand Aditya , Ghorpade Ratnakar
Published: October 2024

A scaffold is a three-dimensional porous structure that is used as a template to provide structural support for cell adhesion and the formation of new cells. Metallic cellular scaffolds are a good choice as a replacement for human bones in orthopaedic implants, which enhances the quality and longevity of human life. In contrast to conventional methods that produce irregular pore distributions, 3D printing, or additive manufacturing, is characterized by high precision and controlled manufacturing processes. AM processes can precisely control the scaffold’s porosity, which makes it possible to produce patient specific implants and achieve regular pore distribution. This review paper explores the potential of Ti-6Al-4V scaffolds produced via the SLM method as a bone substitute. A state-of-the-art review on the effect of design parameters, material, and surface modification on biological and mechanical properties is presented. The desired features of the human tibia and femur bones are compared to bulk and porous Ti6Al4V scaffold. Furthermore, the properties of various porous scaffolds with varying unit cell structures and design parameters are compared to find out the designs that can mimic human bone properties. Porosity up to 65% and pore size of 600 μm was found to give optimum trade-off between mechanical and biological properties. Current manufacturing constraints, biocompatibility of Ti-6Al-4V material, influence of various factors on bio-mechanical properties, and complex interrelation between design parameters are discussed herein. Finally, the most appropriate combination of design parameters that offers a good trade-off between mechanical strength and cell ingrowth are summarized.
A topological perspective on singular canards for critical sets with transverse intersections
Authors: Bonetto Riccardo , Jardón-Kojakhmetov Hildeberto
Published: October 2024

This paper gives a new perspective on singular canards, which is topological in flavour. One key feature is that our construction does not rely on coordinates; consequently, the conditions for the existence of singular canards that we provide are purely geometric. The singularities we study originate at the self-intersection of curves of equilibria of the unperturbed system. Our contribution even allows us to consider degenerate cases of multiple pairwise transverse intersecting branches of the critical set. We employ stratification theory and algebraic geometric properties to provide sufficient conditions leading to the presence of singular canards. By means of two examples, we corroborate our findings using the well-known blow-up technique.
Canards in modified equations for Euler discretizations
Authors: Engel Maximilian , Gottwald Georg
Published: October 2024

Canards are a well-studied phenomenon in fast-slow ordinary differential equations implying the delayed loss of stability after the slow passage through a singularity. Recent studies have shown that the corresponding maps stemming from explicit Runge-Kutta discretizations, in particular the forward Euler scheme, exhibit significant distinctions to the continuous-time behavior: for folds, the delay in loss of stability is typically shortened whereas, for transcritical singularities, it is arbitrarily prolonged. We employ the method of modified equations, which correspond to the fixed discretization schemes up to higher order, to understand and quantify these effects directly from a fast-slow ODE, yielding consistent results with the discrete-time behavior and opening a new perspective on the wide range of (de-)stabilization phenomena along canards.
A formal geometric blow-up method for pattern forming systems
Authors: Jelbart S. , Kuehn C.
Published: October 2024

We extend and apply a recently developed approach to the study of dynamic bifurcations in PDEs based on the geometric blow-up method. We show that this approach, which has so far only been applied to study a dynamic Turing bifurcation in a cubic Swift-Hohenberg equation, can be coupled with a fast-slow extension of the method of multiple scales. This leads to a formal but systematic method, which can be viewed as a fast-slow generalisation of the formal part of classical modulation theory. We demonstrate the utility and versatility of this method by using it to derive modulation equations, i.e. simpler closed form equations which govern the dynamics of the formal approximations near the underlying bifurcation point, in the context of model equations with dynamic bifurcations of (i) Turing, (ii) Hopf, (iii) Turing-Hopf, and (iv) stationary long-wave type. The modulation equations have a familiar form: They are of real Ginzburg-Landau (GL), complex GL, coupled complex GL and Cahn-Hilliard type respectively. In contrast to the modulation equations derived in classical modulation theory, however, they have time-dependent coefficients induced by the slow parameter drift, they depend on spatial and temporal scales which scale in a dependent and non-trivial way, and the geometry of the space in which they are posed is non-trivial due to the blow-up transformation. The formal derivation of the modulation equations provides the first steps toward the rigorous treatment of these challenging problems, which remains for future work.
Spectral and bispectral densities of squared stationary Gaussian processes
Authors: Monahan Adam
Published: October 2024

Extending a classical result for the spectral density of a squared stationary Gaussian process, an expression is presented for the bispectral density of a squared stationary Gaussian process

x

2

(
t
)

x^{2}(t)

in terms of the spectral density of

x
(
t
)

x(t)

. Examples of spectral and bispectral densities are provided for monochromatic, narrowband, Ornstein-Uhlenbeck, and damped harmonic oscillator processes. It is shown that the frequency content of the resulting spectral and bispectral densities generalizes the “sum and difference” frequencies resulting from squaring a monochromatic process. The bispectral densities of squared Gaussian processes are characterized by self-interactions between the narrowband and broadband components of the original process, as well as bispectral ridges resulting from cross-interactions between the narrowband and broadband components. It is shown that the spectral and bispectral densities of an Ornstein-Uhlenbeck process take exactly the same form as those of Correlated Additive-Multiplicative (CAM) noise processes, illustrating the fact that bispectral features cannot unambiguously determine the mechanism responsible for observed skewness. Finally, evidence is provided that while the spectral density of the squared stationary Guassian process provides a good approximation to that of the absolute value of the process, the same is not generally true of bispectral densities.
A heteroclinic surface between two saddle slow manifolds organizing sectors of rotation of mixed-mode oscillations
Authors: Musoke Elle , Krauskopf Bernd , Osinga Hinke
Published: October 2024

We investigate the mechanism underlying the generation of mixed-mode oscillations (MMOs) in the four-dimensional Olsen model for peroxidase-oxidase reaction. MMOs are characterized by a pattern of small-amplitude oscillations (SAOs) and large-amplitude oscillations (LAOs), and they are known to occur in systems with multiple timescales. We identify many co-existing MMO periodic orbits for the Olsen model. We show that these MMOs come in pairs and exist over a sequence of staggered ranges of the timescale separation parameter. In the four-dimensional phase space of the Olsen model, we find that the SAOs come about due to the geometry of a surface of heteroclinic connections between two saddle slow manifolds. We compute the surface of heteroclinic connections through a region of phase space that exhibits a slow passage through a Hopf bifurcation, where the SAOs are generated. Moreover, we compute its intersection curves with two well-chosen hyperplanes. In this way, we show how the surface of heteroclinic connections delimits rotational sectors with given numbers of subsequent SAOs, and also determines the exit from this region of SAOs and the onset of LAOs.
The effect of a cut-off on a model of invasion with dispersive variability
Authors: Popović Nikola , Miao Zhouqian
Published: October 2024

In 1994, a population model of invasion with dispersive variability which represents an extension of the classical Fisher-Kolmogorov-Petrowskii-Piscounov (FKPP) reaction-diffusion equation was proposed by Cook, whereby the population is partitioned into dispersers and non-dispersers. In 1997, an alternative modification to the FKPP equation was suggested by Brunet and Derrida, who included a cut-off in the reaction kinetics to account for the fact that, in many applications, population growth cannot reasonably occur when the population density is below a certain threshold. Here, we combine these two modifications by studying the effect of a Heaviside cut-off in Cook’s extended model. We prove the existence of travelling front solutions; moreover, we determine the correction to the “critical” front propagation speed that is due to the cut-off. Our analysis is based on a combination of geometric singular perturbation theory and the desingularisation technique known as blow-up.
Fast-reaction limits for predator–prey reaction–diffusion systems: improved convergence
Authors: Soresina Cinzia , Tang Bao , Tran Bao-Ngoc
Published: October 2024

The fast-reaction limit for reaction–diffusion systems modelling predator–prey interactions is investigated. In the considered model, predators exist in two possible states, namely searching and handling. The switching rate between these two states happens on a much faster time scale than other processes, leading to the consideration of the fast-reaction limit for the corresponding systems. The rigorous convergence of the solution to the fast-reaction system to the ones of the limiting cross-diffusion system has been recently studied in [Conforto, Desvillettes, Soresina, NoDEA, 25(3):24, 2018]. In this paper, we extend these results by proving improved convergence of solutions and slow manifolds. In particular, we prove that the slow manifold converges strongly in all dimensions without additional assumptions, thanks to the use of a modified energy function. This consists in a unified approach since it is applicable to both types of fast-reaction systems, namely with the Lotka–Volterra and the Holling-type II terms.
Introduction: Perceptual Knowledge and Self-Awareness
Authors: Roessler Johannes , Giananti Andrea
Published: October 2024

The chapter introduces the present volume by setting out three sets of issues addressed in the chapters to follow. First, how should we understand the epistemic authority of perception (as illustrated by J. L. Austin’s famous claim to be able to ‘just see’ that the animal is a pig)? Second, what is the relationship between the authority of perception and self-awareness? Is it in the nature of the former to be manifest from the first-person perspective? Third, is a perceiver’s awareness of seeing or hearing or feeling that p a case of first-person self-knowledge? In what sense is such awareness epistemically ‘immediate’? How does reflection on it affect our understanding of the first-person perspective?
Perceptual Beliefs and Beliefs About Perception
Authors: Snowdon Paul
Published: October 2024

Snowdon’s chapter has two parts. In the first, negative remarks are proposed about belief. It is argued that belief ascriptions are purely theoretical, the nature of belief is unknown, beliefs are passive, the structure of belief is also unknown, in no clear sense do beliefs contain concepts, nor is it obvious that they have content. The same goes for knowledge. The second part engages with how we do know that our knowledge of the external world (which we can call a cognitive state) depends on our perception of the world (which we can call perceptual experience). A model of our perceptual concepts is sketched, and it is argued that the model helps to explain how our explanations of belief and knowledge in terms of perception work.
Perception as a Rational Capacity
Authors: Giananti Andrea
Published: October 2024

In this chapter, I articulate a notion of rational capacity by relying on a broadly Aristotelian tradition that counts among its contemporary representatives philosophers such as Andrea Kern, Matthew Boyle, John McDowell, and, less recently, Anthony Kenny and Gilbert Ryle. I illustrate rational capacities by taking as paradigmatic the case of practical skills, and then I put the notion to work in the context of the epistemology of perception. The main goal is to spell out what it might mean to say that perception as we possess it is a rational capacity.
Knowledge in Action and Knowledge of Perception
Authors: Özaltun Eylem
Published: October 2024

In this chapter I focus on the reasons provided by epistemologists of action in favour of two-factor theories of an agent’s knowledge of her own intentional actions, first to uncover the basic motivation behind these theories, and second to show that these motivating insights can be better captured in a non-factorizing approach. I diagnose that the main difficulty of understanding how an agent knows her own intentional actions stems from the difficulty of giving a unified account of two important characteristics of this way of acquiring knowledge: immediacy and fallibility. Then, I argue that the basic obstacle in the way of such a unified account is a wrong conception of the immediacy of this knowledge. I propose that the immediacy of our perceptual states is the right model to capture the sort of immediacy an agent’s knowledge has. By drawing on the perception model, I sketch a one-factor theory of knowledge in action.
Spontaneity Without Rationality: A Kantian Approach to Self-Consciousness and Perceptual Content
Authors: Ginsborg Hannah
Published: October 2024

A number of philosophers, inspired by Kant’s view of self-consciousness as consciousness of spontaneity, have understood self-consciousness as requiring rational agency with respect to one’s beliefs and desires. This leads to a demanding conception of self-consciousness, which excludes the ascription of self-consciousness to children who are too young to appreciate reasons. I offer an interpretation of the role of spontaneity in perceptual experience which suggests that there can be spontaneity, in Kant’s sense, without rational agency. The consciousness of spontaneity, on my reading of Kant is the consciousness of normative constraint in one’s thinking, and, as I argue through consideration of sorting behaviour in small children, one can be conscious of normative constraint without recognizing reasons. This leads to a less demanding, but still recognizably Kantian, conception of self-consciousness, one which accommodates the idea that small children can be self-conscious.
Oligoribonucleotide interference-PCR-based methods for the sensitive and accurate detection of KRAS mutations
Authors: Fujita Hiroaki , Fujita Toshitsugu , Ishido Keinosuke , Hakamada Kenichi , Fujii Hodaka
Published: October 2024

Pancreatic cancer is an aggressive malignancy with a poor prognosis. Single-nucleotide mutations in the KRAS gene are detected in the majority of patients with pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer. Identifying KRAS mutations by liquid biopsy could be effective for detecting de novo and recurrent PDAC; however, sensitive and accurate detection remains challenging. We examined the utility of oligoribonucleotide interference-PCR (ORNi-PCR) followed by real-time PCR or droplet digital PCR (ddPCR) for detecting KRAS single-nucleotide mutations by liquid biopsy. A model of cell-free DNA was used to demonstrate that the ORNi-PCR-based methods are more sensitive and accurate for detecting KRAS mutant DNA than conventional real-time PCR or ddPCR. ORNi-PCR-based methods could be useful for early detection of de novo and recurrent PDAC by liquid biopsy for cancer diagnosis.
Melanoma as a detection-dependent cancer: proxy measures of screening and surveillance associated with 3-year incidence of detection procedures for skin cancer in a national prospective study
Authors: Pandeya Nirmala , Olsen Catherine M , Neale Rachel E , Whiteman David C
Published: October 2024

Background

Increased levels of skin detection activities are suspected of driving recent rapid increases in melanoma incidence. While ecological studies report rising rates of skin biopsies in many industrialized populations, few studies have accessed individual-level clinical data to test the hypothesis that people exposed to skin screening and surveillance go on to experience higher levels of biopsies and excisions, and a higher incidence of melanoma.

Objectives

To measure the incidence rates of detection events and melanoma diagnoses in a national cohort during follow-up, stratified according to screening or surveillance activities in the index year.

Methods

We conducted a prospective cohort study of 10 674 200 adults using linked data from Australia’s universal health insurance scheme (2011–2016). Participants who underwent biopsies or who were diagnosed with skin cancer in 2011–12 were excluded. We then defined participants as surveilled, screened or unscreened for skin cancer based on medical claims occurring in 2013. We compared rates of biopsies, excisions for suspected melanoma and excisions for histologically confirmed melanoma during follow-up (2014–2016).

Results

After adjusting for sociodemographic factors, screened people were significantly more likely than unscreened people to undergo skin biopsies [rate ratio (RR) 2.59, 95% confidence interval (CI) 2.56–2.63], excisions for suspected melanoma (RR 2.57, 95% CI 2.53–2.60) and excisions for confirmed melanoma (hazard ratio 3.32, 95% CI 3.24–3.40) during follow-up. Similarly elevated rates of subsequent diagnostic events were observed for the surveilled group. Importantly, rates of detection and rates of melanoma remained elevated in each of the subsequent years of follow-up among those who were screened or surveilled in the index year.

Conclusions

People undergoing skin screening or surveillance subsequently experience higher rates of diagnostic scrutiny and higher rates of melanoma.
Clinical correlates of dopamine transporter availability in cross-sectional and longitudinal studies with [18F]FE-PE2I PET: independent validation with new insights
Authors: Honhar Praveen , Ebrahimian Sadabad Faranak , Tinaz Sule , Gallezot Jean-Dominique , Dias Mark , Naganawa Mika , Yang Yanghong , Henry Shannan , Hillmer Ansel T , Gao Hong , Najafzadeh Soheila , Comley Robert , Nabulsi Nabeel , Huang Yiyun , Finnema Sjoerd J , Carson Richard E , Matuskey David
Published: October 2024

[18F]FE-PE2I PET is a promising alternative to single positron emission computed tomography–based dopamine transporter (DAT) imaging in Parkinson’s disease. While the excellent discriminative power of [18F]FE-PE2I PET has been established, so far only one study has reported meaningful associations between motor severity scores and DAT availability. In this study, we use high-resolution (∼3 mm isotropic) PET to provide an independent validation for the clinical correlates of [18F]FE-PE2I imaging in separate cross-sectional (28 participants with Parkinson’s disease, Hoehn–Yahr: 2 and 14 healthy individuals) and longitudinal (initial results from 6 participants with Parkinson’s disease with 2-year follow-up) cohorts. In the cross-sectional cohort, DAT availability in the putamen and substantia nigra of patients with Parkinson’s disease showed a significant negative association with total motor severity (r = −0.59, P = 0.002 for putamen; r = −0.46, P = 0.018 for substantia nigra), but not tremor severity. To our knowledge, this is the first observed association between motor severity in Parkinson’s disease and DAT availability in the substantia nigra. The associations with motor severity in most nigrostriatal regions improved if tremor scores were excluded from motor scores. Further, we found significant asymmetry in DAT availability in the putamen (∼28% lower DAT availability within the more-affected side of the putamen), and DAT-based asymmetry index for the putamen was correlated with asymmetry in motor severity (r = −0.60, P = 0.001). In the longitudinal study, [18F]FE-PE2I PET detected significant annual percentage reduction of DAT availability at the individual level in the putamen (9.7 ± 2.6%), caudate (10.5 ± 3.8%) and ventral striatum (5.5 ± 2.7%), but not the substantia nigra. Longitudinal per cent reduction in DAT availability within the putamen was strongly associated with increase in motor severity (r = 0.91, P = 0.011) at follow-up, demonstrating the high sensitivity of [18F]FE-PE2I PET in tracking longitudinal changes. These results provide further evidence for the utility of [18F]FE-PE2I as an important in vivo PET biomarker in future clinical trials of Parkinson’s disease.
Revisiting secondary mitral regurgitation threshold severity: insights and lessons from the RESHAPE-HF2 trial
Authors: Lancellotti Patrizio , Sugimoto Tadafumi , Bäck Magnus
Published: October 2024

Aims

This article revisits the severity threshold for secondary mitral regurgitation (MR), focusing on insights and lessons from the RESHAPE-HF2 trial. It aims to challenge the traditional effective regurgitant orifice area (EROA) threshold of ≥0.40 cm2 used for intervention, suggesting that earlier intervention may benefit patients with lower EROA. It also explores how transcatheter edge-to-edge repair (TEER) improves outcomes in patients with secondary MR and assesses the impact of left ventricular (LV) remodeling on treatment success.

Methods and Results

The RESHAPE-HF2 trial evaluated the use of TEER in patients with moderate-to-severe secondary MR, comparing outcomes in those with an EROA ≥0.2 cm2 and no extensive LV remodeling. TEER significantly reduced heart failure hospitalizations and improved quality of life in these patients. This supports the notion that patients with less severe MR, who still show symptoms despite optimal medical therapy, may benefit from earlier intervention. Comparisons with COAPT and MITRA-FR trials underscored the importance of selecting patients based on MR severity relative to LV dilatation.

Conclusions

The RESHAPE-HF2 trial highlights the need to reconsider the current EROA threshold for secondary MR intervention. TEER has shown to be beneficial even in patients with lower MR severity, suggesting that earlier intervention could improve outcomes. A more dynamic and integrated approach, considering both MR severity and LV remodeling, is essential for optimizing patient selection and treatment success.
Trends and risk factors analysis of aortic aneurysm mortality in China over thirty years: based on the global burden of disease 2019 data
Authors: Huang Hongliang , Tang Liming , Liu Chunjiang , Jin Gan
Published: October 2024

Objectives

This study aims to analyse the variation in mortality burden of aortic aneurysms (AAs) and explore the associated risk factors based on Global Burden of Disease (GBD) 2019 data, investigating the mortality burden of AA in China.

Methods and results

Using GBD 2019 data, the mortality burden of AA in China from 1990 to 2019 was analysed. The age-period-cohort model was utilized to analyse time trends, period, and cohort effects of four attributable risk factors of AA by age. In 2019, the total number of AA deaths in China increased by 136.1% compared to 1990, while the age-standardized mortality rate (ASMR) decreased by 6.8%. Male deaths and ASMR were higher than those of females, and ASMR increased with age. Whether viewed overall [average annual percent change (AAPC): −0.261, 95% confidence interval (CI): −0.383 to −0.138] or by sex (female AAPC: −0.812, 95% CI: −0.977 to −0.646; male AAPC: −0.011, 95% CI: −0.183–0.162), the ASMR for AA in China has shown a declining trend since 1990. Attributable risk factors such as high blood pressure, a diet high in sodium, smoking, and lead exposure increase AA mortality with age. Smoking mortality peaks between ages 80 and 85. The cyclical effect of high blood pressure on AA mortality significantly increases, while the cyclical effects of the other three risk factors decrease. For the population born after 1940, the cohort effect of high systolic blood pressure (SBP), a diet high in sodium, and smoking increased, while the cohort effect of lead exposure decreased. The local drift values of high SBP, a diet high in sodium, and smoking decreased, while the local drift value of lead exposure increased. High SBP was identified as the most significant attributable risk factor for AA mortality burden among both males and females, and smoking was another major attributable risk factor, particularly in males.

Conclusion

From 1990 to 2019, fatality due to AA in China increased notably, but the ASMR showed a decreasing trend. The mortality rate of AA was influenced by age, sex, and attributable risk factors, with elderly male smokers carrying a heavy burden of death. Moreover, tobacco control and treatment of hypertension should be strengthened to reduce the burden and its impact on AA.
Adult Socioeconomic Position Mediates the Association Between Childhood Socioeconomic Position and Later-Life Frailty Trajectory: A Nationally Representative Cohort Study
Authors: Guo Yanfei , Ng Nawi , Hassler Sven , Wu Fan , Jonasson Junmei Miao
Published: October 2024

Background and Objectives

Early-life risk factors influence the aging process in the short term and shape its trajectory in the long term. We aim to (1) explore the association between childhood socioeconomic position (cSEP) and frailty trajectories and (2) test whether adult socioeconomic position (aSEP) mediates the association between cSEP and frailty trajectories.

Research Design and Methods

We analyzed 4 waves of the China Health and Retirement Longitudinal Study data. The frailty index was estimated based on the number of individual deficits across 40 indicator variables. Principal component analysis was used to generate cSEP and aSEP. Group-based trajectory models were used to identify the patterns of frailty trajectories over time. Causal mediation analysis was conducted to determine whether the aSEP mediated the association between cSEP and frailty trajectories.

Results

We identified 3 distinct trajectories of frailty progression. Low cSEP was significantly associated with “High and increasing frailty trajectory” (odds ratio [OR] = 1.76, 95% confidence intervals [95% CI]: 1.38–2.23; adjusted OR = 1.55, 95% CI: 1.22–1.97). About 30% of the cSEP effect on rising frailty trajectory was mediated through the aSEP, and there is a significant gender disparity in the mediating effect of aSEP (18% among men and 51% among women, respectively).

Discussion and Implications

Our findings suggest that policies that initially benefit children will yield well-being benefits as they reach adulthood. Promoting ongoing cSEP advantages increases the likelihood of delaying frailty progression in later life. This study underscores the critical importance of addressing social determinants of health throughout one’s life course to foster healthy aging and diminish health disparities in later stages of life.