The European Physical Journal Plus最新文献

Particle beam therapy is becoming increasingly popular as an advanced cancer treatment method, and currently proton and (stable) carbon ion beams are used clinically. Recently, in-beam positron emission tomography (PET) has been investigated for dose monitoring technique during particle therapy. However, the signal-to-noise ratio of in-beam PET images is poor due to the low yield of positron emitters. On the contrary, radioactive ion (RI) beams is ideally suited to particle therapy using in-beam PET due to its high signal-to-noise ratio. In addition, RI beams enable more accurate analysis of the biological washout effect than conventional stable beam irradiations do. These advantages have been clearly demonstrated in many animal studies with prototyped PET systems. On the other hand, there are several issues that limit clinical use of RI beams such as the low RI beam intensity, large momentum distribution, and the limited number of RI beam facilities. This article reviews the state-of-the-art research and development for applications of RI beams to particle beam therapy.

Calcium ((hbox {Ca}^{2+})) store and mitochondria play very important role in cell signaling. Despite extensive inquiry into calcium dynamics across diverse cell types, including hepatocytes, comprehension of the interconnected dynamics of cytosolic and mitochondrial calcium in normal and obese cellular milieus remains rudimentary. Calcium influx can manifest as either a transient blip or a more sustained puff, contingent upon cellular conditions. A puff, which is formed when several (hbox {IP}_{3}) receptors open simultaneously, is larger than a blip, which is a tiny signal produced by a single (hbox {IP}_{3}) receptor (IP3R) opening. These occurrences demonstrate cell’s capacity to regulate (hbox {Ca}^{2+}) signaling precisely and vary from opening of a single channel (blip) to coordinated opening of several channels in a cluster (puff). One-dimensional model proposed by earlier researchers is able to incorporate the effect of only point source like blip but are not capable of providing effects of line sources like puffs. Higher dimensional model development is required to gain a deeper understanding of the local effects of different mechanisms and feedbacks in hepatocyte cells. Thus, a two-dimensional model for hepatocytes under normal and obese conditions, integrating a reaction-diffusion equation to delineate coupled dynamics of cytosolic and mitochondrial calcium, encompassing blip and puff phenomena has been proposed in this paper. Additionally, the ramifications of (hbox {Ca}^{2+}) signaling on ATP generation and degradation rates, alongside the open channel probability of chloride and potassium ions has been investigated. Numerical simulations are executed employing the linear finite element method, spatially and Crank-Nicolson method, temporally. Furthermore, a comparative assessment of (hbox {Ca}^{2+}) signaling, ATP generation, degradation rates and open channel probability of chloride and potassium ions in normal versus obese hepatocytes has been done.

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The incorporation of multi-walled carbon nanotubes (MWCNTs) with spinel ferrites can lead to enhanced properties and performance in the resulting nanocomposite. MWCNTs known for their excellent mechanical strength, electrical conductivity and thermal stability can contribute positively to the overall characteristics of the composite. In this research paper, the solgel auto-combustion technique was used to synthesize zinc ferrite (ZnFe₂O₄) nanoparticles. Their (ZnFe₂O₄)_1-x(MWCNTs)_x nanocomposites with content MWCNTs as (x = 0, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared through a route known as ultrasonication route. Through X-ray diffraction analysis (XRD), the well-defined crystal arrangement and purity of the nanocomposite were confirmed. The loading and the dispersion of the MWCNTs on the surface of the nanoparticle were conducted using transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FTIR) was used to analyze various vibrational modes. The frequency-dependent dielectric characteristics were investigated by an impedance analyzer in the applied frequency range of 1 MHz to 3 GHz under standard temperature conditions. The dielectric properties including real and imaginary parts of dielectric constant, tangent loss, AC conductivity, real and imaginary parts of impedance and real and imaginary parts of electric modulus have drastically changed with the incorporation of the MWCNTs in pure nanoparticle’s matrix. The magnetic properties of the nanocomposites at room temperature in the range of − 25 to 25 kOe were investigated by utilizing VSM (vibrating sample magnetometery). The magnetic parameters such as maximum magnetization saturation (M_mxs), coercivity (H_c), remanence (M_r) and anisotropic constant (K) as massively decreased with the addition of the MWCNTs. The optimized dielectric and magnetic characteristics of these nanocomposite suggest their potential use in high-frequency equipment, microwave devices and high energy storage devices.

The present research work aims to investigate a steady laminar flow of a nano-lubricant Zinc Oxide–Society of Automotive Engineers 50 alias between two concentric cylinders under the effects of Ohmic dissipation and thermal radiation. With the help of conservation laws, a theoretical controlling model for the flow and heat transmission has been developed. The model consisting of a system of partial differential equations has been reduced to a system of nonlinear ordinary differential equations by using similarity transformation. Solution approximation to the resulting system is carried out using artificial neural networks along with the Bayesian regularization technique. The reference data to train and test the network has been obtained by employing the Lobatto IIIA algorithm. To show the correctness of the approximation algorithm, different metrics, such as mean squared loss, error histogram, regression analysis, and function fit plots, are observed. Our graphical simulation shows that the Ohmic dissipation directly leads to an increase in temperature by converting electrical energy into heat. Conversely, the local rate of heat transfer falls due to Ohmic dissipation.

Characterizing the coherence properties of illumination is essential for assessing imaging quality and system performance in various optical systems. This letter aims to highlight Hartmann sensor tomography, a novel approach integrating wavefront sensing with tomographic reconstruction to measure spatial coherence without scanning. Operating in a non-classical regime, the technique utilizes a custom-designed mask and a maximum-likelihood reconstruction algorithm to estimate the coherence matrix with high precision. The method is experimentally validated using partially coherent sources from collimated multimode fibers with varying core diameters, providing diverse test scenarios. These results are compared with the theoretical predictions of the van Cittert-Zernike theorem, showcasing excellent agreement and demonstrating the method’s ability to reconstruct complex coherence structures accurately and efficiently. Hartmann sensor tomography offers a fast and robust alternative to conventional interferometric techniques for analyzing partially coherent fields, paving the way for applications in imaging, diagnostics, adaptive optics, and other areas where rapid and precise coherence characterization is critical.

In this work, we research the properties of neutron stars using the nonlinear relativistic mean-field theory and consider multiple degrees of freedom inside neutron stars, including hyperons and (Delta) resonances. We investigate different coupling parameters (x_{sigma Delta }) between (Delta) resonances and nucleons and compare the differences between neutron stars with and without strange mesons (sigma ^*) and (phi) These effects include particle number distributions, equations of state (EOS), mass–radius relations, and tidal deformabilities. To overcome the “hyperon puzzle,” we employ the (sigma -cut) scheme to obtain neutron stars with masses up to (2M_{odot }). We find that strange mesons appear at around 3(rho _0) and reduce the critical density of baryons in the high-density region. With increasing coupling parameter (x_{sigma Delta }), the (Delta) resonances suppress hyperons, leading to a shift of the critical density toward lower values. The early occurrence of (Delta) resonances may play a crucial role in the stability of neutron stars. Strange mesons soften the EOS slightly, while (Delta) resonances predominantly soften the EOS in the low-density region. By calculating tidal deformabilities and comparing with astronomical event GW170817, we find that the inclusion of (Delta) resonances decreases the radius of neutron stars.

This article modifies a mathematical dynamics model to analyze mosquito control strategies using the combined incompatible and sterile insect techniques. To regulate mosquito populations precisely, the model uses a Holling-II type proportional saturation release. The study first proves the existence of up to three equilibria and analyzes stability. It then investigates the potential saddle-node bifurcation that occurs under the threshold release rate, which is crucial for understanding mosquito population dynamics and developing an optimal control strategy. Numerical simulations confirm the accuracy of the model and show its dynamic behavior. The results suggest that by precisely controlling the release rate, mosquito population density can be effectively reduced, interrupting disease transmission chains.

The primary goal of this research is to present an improved shock wave theory that takes into account the gaseous non-ideality for a monatomic gas system composed of hard-sphere molecules using simplified van der Waals equation of state at high Mach numbers. In non-ideal gas, dimensionless conservation equations and new Rankine–Hugoniot conditions are given. The SSTNM (similar simplified translational non-equilibrium model) and OBurnett constitutive equations with non-ideal parameters are extended. The differential equations of improved theory for shock waves are established and solved. The validity of constitutive relations in non-ideal gas situations is proved, and the results are verified by direct simulation Monte Carlo methods. By examining the orbital structure, internal structure of shock waves and structural parameters of density–temperature separation, it becomes apparent that the improved shock wave theory considering the gaseous non-ideality has a better predictive effect than treating it as an ideal gas. Further experimental verification using density results indicates that the higher the Mach number, the closer the results predicted by the two constitutive equations are to the experimental results in the prediction region they are good at. This article improves the prediction effect of the shock wave structure using the improved shock wave theory, and it also introduces novel perspectives and strategies for avoiding the use of high-order constitutive relations that are prone to numerical instability.

Using thermometers in PCM solidification experiments is a common method. But, solidification particularly at the primary stage is the result of the cooperation of both natural convection and conduction heat transfer. So, the presence of thermometer probes and wires can affect the natural convection and therefore can affect the solidification rate. Additionally, fewer photos are available for qualitative validation of numerical solidification results. Especially the shape of the cavity formed at the final stage is a critical benchmark for numerical validation. In this study, a novel method is proposed to directly measure the PCM solidification rate based on the image analysis and processing technique. In this method, images are prepared from the sample in equal time intervals and under controlled light and temperature conditions. By using image processing techniques, the solid layer boundary is extracted, and the number of pixels in this enclosed area is divided by the number of pixels in the solid area at the final step. The method was applied to paraffin solidification in a horizontal cylinder. The problem was also numerically simulated by the multiphase method (VOF), and a good agreement between experimental and numerical results was observed. The RMSE was 3.2%. The cavity shape was also recorded. Based on the experiment, there is a narrow solid strip on the vessel wall atop the solid core and also a circular cavity at the center (slightly close to the top). This cavity is inevitable because the solid density is more than liquid density and, consequently occupies less volume than liquid. The presence of measuring instruments may disrupt the flow path lines, or a solid core may stick around the instrument's probe which can change the freezing rate or affect results in other ways. But, since in this method, no measuring device, such as a thermocouple, is in direct contact with the fluid, these undesirable effects vanish.

This study investigates the potential for biological systems to be governed by a variational principle, suggesting that such systems may evolve to minimize or optimize specific quantities. To explore this idea, we focus on identifying Lagrange functions that can effectively model the dynamics of selected population systems. These functions provide a deeper understanding of population evolution by framing their behavior in terms of energy-like variables. We present an algorithm for generating Lagrangian functions applicable to a family of population dynamics models and demonstrate the equivalence between two-dimensional population models and a one-dimensional Newtonian mechanical analog. Furthermore, we explore the existence of conservation laws for these models, utilizing Noether’s theorems to investigate their implications.