The European Physical Journal Plus最新文献

This study offers an in-depth investigation of tuberculosis (TB) transmission dynamics and control strategies through a deterministic compartmental SEIT epidemic model. The stability of the disease-free equilibrium (DFE) locally and globally is analyzed corresponding to a basic reproduction number less than one ((R_0<1)). Additionally, our analysis uncovers the presence of backward bifurcation, which allows for the coexistence of disease-free and endemic equilibria even when (R_0<1). A sensitivity analysis highlights key parameters affecting (R_0<1) with the contact rate ((beta )) and progression rate ((alpha )) being the most influential. These findings inform the creation of effective public health policies to increase awareness through media and education ((mu _1)), enhance testing rates ((mu _2)), and improve treatment services ((mu _3)). The Pontryagin’s Maximum Principle is applied to determine the optimal control levels for the considered three intervention strategies ((mu _1,mu _2,mu _3)) over the simulation period. The results indicate that the objective function is influenced by the relative costs of each control measure and the optimal system is accessible numerically also. The findings suggest that interventions focused solely on media or educational awareness can be highly cost-effective, achieving low average cost-effectiveness ratio (ACER) alongside a high infection reduction ratio (IAR). These insights provide valuable guidance for public health policymakers in designing effective tuberculosis control programs. Ultimately, our research underscores the importance of comprehensive intervention strategies to successfully curb the spread of TB.

In the field of high-performance thermoelectric energy conversion, achieving glass-like ultralow lattice thermal conductivity in crystalline solids with high electrical conductivity remains a significant challenge. We uncovered that the monolayer Ca₃Sn₂S₇ chalcogenide perovskite exhibits an extraordinary combination of ultra-low lattice thermal conductivity and high electrical conductivity. The lattice thermal conductivity ((kappa_{l})) of monolayer Ca₃Sn₂S₇ is as low as 1.27Wm⁻¹ K⁻¹ at room temperature and decreases to 0.42Wm⁻¹ K⁻¹ at 900 K. Our in-depth analysis of the phonon spectra, phonon density of states (PDOS), potential energy variations of atoms deviating from equilibrium positions, and studies on atomic displacement parameters (ADPs) attribute this exceptionally low (kappa_{l}) predominantly to the rattling model mechanism. Furthermore, monolayer Ca₃Sn₂S₇ is identified as a narrow band direct semiconductor, possessing a bandgap of 0.47 eV and exhibiting high electrical conductivity. The monolayer Ca₃Sn₂S₇ reaches its peak ZT values of 7.8 for p-type and 5.2 for n-type at 600 K. The monolayer Ca₃Sn₂S₇ is considered a potential material for high-performance thermoelectric materials.

The SORGENTINA-RF project aims at developing a 14 MeV fusion neutron source that relies on a deuterium/tritium ion accelerator to produce ⁹⁹Mo for medical applications. The ion accelerator is tested initially in hydrogen using a dumping system in order to assess its performance. The 300 keV–830 mA proton beam interacts both with the residual gas in the drift tube of the accelerator and with the beam dump, resulting in a series of radiative processes. In principle, these phenomena could rise organizational challenges related to the safety of operators and technical issues such as overheating of the drift tube. Analytical and numerical methods are used to estimate the magnitude of the impact of the unwanted radiation and to adopt appropriate and adequate operating measures.

Pathogenic mutations in the BRCA1 gene are among the most significant genetic risk factors for breast cancer. Identifying these mutations is crucial for advancing prevention and treatment strategies. A substantial portion of genetic variants in BRCA1 remains unclassified due to limited functional evidence. Mutations in the Interesting New Gene (RING) and BRCA1 C-terminal (BRCT) domains are particularly associated with increased cancer risk. This study aims to identify and analyze novel mutations in these domains. Seven newly identified mutations—Q12H, K20D, and E84G in the RING domain, and Y1666D, T1675S, T1681A, and L1764Q in the BRCT domain—were evaluated using molecular dynamics simulations. The simulations revealed significant changes in the protein stability, flexibility, compactness, hydrogen bonding, and solvent-accessible surface area, with BRCT domain mutations showing more pronounced effects. This study represents the first comprehensive computational analysis to assess the structural and functional impact of these novel mutations and predict stabilization possibilities. By elucidating the conformational dynamics of BRCA1 mutations, our findings provide a foundation for experimental validation and the development of targeted therapeutic interventions.

Neutron focusing lenses are very important for various applications in fundamental science, industry, or even medicine. Conventional Fresnel zone plates (FZP) were successfully used as neutron focusing lenses. However, several difficulties are arisen when larger dimension (at the order of 10 cm) focal lenses are demanded for some applications. Here, we proposed a neuron network metalens design method based on D²NN algorithm. In this work, several neutron power focusing metalenses were designed for neutron energies from cold to epithermal, with size lengths from a few mm to 140 mm, and a focal length range from 60 mm to 13.5 m. Based on our simulations, clear focusing patterns were observed and were consistent with previous experiments. The estimation value of power focusing efficiency could be as high as 20%.

The Circular Electron-Positron Collider (CEPC) performs precision measurements of Higgs boson properties, which require MeV-level precision in beam energy calibration. In the W/Z factory mode, the requirements for beam energy calibration are an order of magnitude higher than those in the Higgs operation. To address this need, we utilize a beam energy calibration scenario based on inverse Compton scattering, using a laser beam heading on the electron bunch and a bending dipole. Our Monte-Carlo simulations demonstrate that the beam energy can be calibrated to a precision of about 1 MeV, using the position distribution of scattered photons and scattered electrons. Additionally, the systematic deviations caused by the magnetic field and the synchrotron radiation are analyzed. The error of the method of measuring the scattering position by measuring the scattering angle is divided into two parts, which are 9.75 and 5.76 MeV, respectively. The estimated systematic deviation of the calibration energy caused by the electron beam emittance angle is approximately 3.4 keV.

Recent technological advancements have facilitated the deployment of distributed, cost-effective, and energy-efficient wireless sensor networks that are increasingly applied in various industrial and civil sectors, including the radiological and nuclear domains. In such a context, the role of radiation monitoring and early detection in ensuring the safety of both workers and the public during standard operations and in response to hazardous events is well recognized. In normal operations, a robust radiation monitoring framework is necessary to maintain compliance more easily with regulatory standards and prevent accidents or leaks from occurring. In response to hazardous events, early radiation detection is essential to the safety of emergency responders, citizens, and the environment. To this aim, this study introduces an autonomous device designed for enhanced radiological and nuclear emergency management capable of gamma rays and thermal neutrons detection. The unit features ultra-low power consumption, making it suitable for long-term placements in hard-to-reach or sensitive areas, and it employs long-range radio technology to ensure wireless and reliable data transmission over long distances, even in challenging environments. Its extended battery life, robust networking capabilities, and autonomous functionality make it suitable for continuous monitoring in critical areas such as nuclear power plants, urban radiation monitoring locations, post-disaster zones, and healthcare radiology units. Leveraging long-range radio technology ensures decentralized and secure monitoring without relying on local internet networks. This device addresses a critical need in radiological and nuclear emergency management, providing reliable measurements, longevity, and easy integration with existing networks and Internet-of-Things technologies.

Graphical abstract

The stopping force of energetic ions in matter is of importance in many aspects of materials research and development using ion beams. Common applications include ion implantation, ion beam modification of materials and ion beam analysis. In most instances stopping force data is obtained from semi-empirical and theoretical formulations. While the accuracy of these data sources is now generally acceptable for light ions (H, He), more work still needs to be done to improve their predictive accuracy for heavier ions (Z ≥ 6). In this work we describe a simple experimental procedure used to generate stopping force data of carbon (C), silicon (Si) and cobalt (Co) ions through molybdenum (96Mo) over a continuous range of energies between 0.05 MeV/u and 0.5 MeV/u. The measurement was carried out using a Time of Flight – Elastic Recoil Detection Analysis (ToF-ERDA) set up. A 40 MeV 197Au9+ beam was used to recoil C, Si and Co ions from thick carbon, silicon dioxide and cobalt targets, respectively, towards a Mo stopper foil. The energy loss of the incident recoils through the stopper foil was calculated from the measured ToF across a fixed path length, with and without the stopper foil, and the stopping force then determined as the ratio of the energy loss to the measured foil thickness. Results were compared to semi-empirical calculations using Ziegler's Stopping and Range of Ions in Matter (SRIM) code, Sigmund and Schinner's ab initio theory as implemented in their PASS code and ab initio calculations using Grande and Schiewietz’s Convolution approximation for swift Particles (CasP 6.0) code. Results show notable differences between the theoretical formulations themselves, which makes comparison with experiment an intractable task. That said though, CasP performs better than the other two codes at low energies for the three ions studied, more so for carbon. At higher energies, towards the Bragg peak, all three codes overestimate experiment, to varying degrees.

In the present work, a theoretical attempt using triaxial projected shell model (TPSM) has been made to understand and confirm the structural evolution observed in even–even isotopes (A = 152–164) of Gd ((Z=64)) nucleus. The TPSM study of yrast, (gamma), (gamma gamma)-bands provides a reasonable description about the triaxial nature of these isotopes. The E-GOS plots along with (R_{42})-ratios predict shape transition phenomenon along isotopic chain under study. Further, backbending in moment of inertia, g factors, transition probabilities, energy staggering in (gamma)-bands, etc., have also been calculated and found to be in good agreement with the available experimental data.